Agetolites is a problematic Late Ordovician genus possessing traits of both tabulate and rugose corals. The presence of numerous mural pores has often been considered to indicate a relation to tabulates, although an affinity to rugosans has also been proposed, based mainly on well-developed septa that alternate in length. To further consider the taxonomic position of Agetolites, growth characteristics of coralla representing three species from the Xiazhen Formation in South China are documented and assessed, focusing on modes of corallite increase. Three major modes of increase are recognized. By far the most common mode involves the development of an offset from a connective mural pore, without a clear relationship to a particular parent corallite. This mode of increase is usually associated with corner pores, but in one case occurs at a wall pore. The lateral mode of increase, which is relatively uncommon, is a typical feature in corallites along the boundary of intergrowths with stromatoporoids. The axial mode of increase is rare, occurring during rejuvenation of a damaged corallite or during regeneration following termination of a corallite. The mode of corallite increase that is characteristic of Agetolites, involving a connective mural pore and occurring without evidence of a particular parent, supports the interpretation that this genus is not a rugosan or a typical favositid tabulate. Mural pores are unknown in rugosans, and offsets arise from distinct parent corallites in favositids. The Ordovician genus Lichenaria, considered a representative of the most primitive stock of tabulate corals, shows the closest similarities with types of increase in Agetolites. Certain aspects of lateral and axial increase in Agetolites are comparable to features in a few more genera of Ordovician tabulates, further supporting a tabulate affinity. The phylogenetic relation of Agetolites to those and other tabulate genera, however, remains unresolved.

New and old species and genera of the family Guadalupiidae (spherulitic hypercalcified demosponges of the order Agelasida) are described or redescribed from the West Texas Permian. The entire family is reviewed and observations are made on the epibionts, growth patterns, functional morphology, ecological relationships, morphologic variability, modular structure, and evolutionary history of these largely reef-dwelling sponges. The stratigraphic distribution of species is also noted; many are limited and can define zones. The new genera Exovasa and Incisimura and the new species Guadalupia auricula, G. cupulosa, G. ramescens, G. microcamera, G. vasa, Cystothalamia megacysta, Lemonea simplex, Incisimura bella, and Exovasa cystauletoides are described. Almost all previously published taxa are redescribed and in some cases redefined. The Guadalupiidae are unique among hypercalcified sponges in having a modular thalamid layer (thalamidarium) covered on the exhalant surface by a non-modular stromatoporoid-like layer (trabecularium).

The new thin-walled vasiform dictyospongid hexactinellid, Tiddalickia manitobensis, is described from the Ordovician Red River Formation at McBeth Point on Lake Winnipeg, Manitoba. Vertical spicule bundles are an outer? part of the wall and horizontal spicule bundles an inner? different level within the wall. Bundle quadrules are only half the size of those in Tiddalickia quadrata Rigby and Webby, 1988. A complete anthaspidellid lithistid, Aulocopella winnipegensis Rauff, 1895, is described from a glacial erratic recovered from near Reston, Manitoba.

The editor of the Zoological Record has kindly informed me that the generic name Polysiphonia Finks, 1995, (class Calcarea, order Murrayonida, family Maeandrostiidae) (Finks, 1995, page 4) is preoccupied (Mrs. M. Joan Thorne, personal commun., 1996). I therefore rename it Polysiphonaria.

The extensive fauna of vertebrates from the Lower Devonian Water Canyon Formation of Utah was initially reported and described by Branson and Mehl (1930, 1931), and subsequently described in detail by Denison (1952, 1953, 1958, 1967). A major part of the fauna consists of heterostracans, particularly pteraspidids (Denison, 1953, 1967), and to date six species are known from the Water Canyon Formation. This fauna comes from the upper Emsian and is similar in age to that of the Beartooth Butte Formation of Wyoming and Montana, and also to faunas recently reported from Nevada and California (Elliott, 1989; Ilyes and Elliott, 1991, 1992).

Cythere ikeyanoriyukii n. sp., an extant phytal ostracode genus, was obtained from the Middle Eocene McIntosh Formation in the Doty Hills, western Washington State, USA. It was associated with eleven taxa, which are extant phytal and shelfal genera such as Loxocorniculum, Xestoleberis, Ambostracon, Coquimba, and Acanthocythereis. The presence of Cythere in this assemblage is surprising and indicates that the first appearance of this genus was middle Eocene time at the latest, or at least 20 Ma earlier than previously thought. Cythere did not originate in the Pacific Ocean around Japan as previously thought, but instead must have migrated from the northeastern Pacific to the northwestern Pacific between middle Eocene and early Miocene time.

The suborder Phacopina, characterized by schizochroal eyes, is among the most common groups of trilobites in Devonian strata. The marine sediments of the Famennian in western Junggar, Xinjiang, contain abundant low-disparity phacopids, which have previously been designated to Omegops accipitrinus mobilis, Phacops circumspectans tuberculosus, and Omegops cornelius on the basis of small numbers of poorly preserved specimens. In this study, these phacopids were identified as two new species of Omegops, O. honggulelengensis n. sp. and O. xiangi n. sp., on the basis of nearly 200 well-preserved specimens. The intraspecific variations of eye lenses of these specimens were quantitatively analyzed. On the basis of differences in the total number, number of dorsoventral files, and arrangement of the eye lenses, the absence of lenses in the middle part of the visual surface, and asymmetry of the number and/or arrangement of lenses in the two eyes, it was concluded that the reasons for intraspecific variation in eye lenses of Late Devonian Omegops from western Junggar were different from previously described factors but were likely genetic or embryological malfunctions or abnormalities caused by pathological conditions. Diversity of lenses in the schizochroal eyes shows that the number and arrangement of eye lenses was not stable in Phacopina. Therefore, many specimens are needed for quantitative study to determine the true characteristics of the number or arrangement of eye lenses when these features are used in the systematic taxonomy of Phacopina.

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The dalmanitid trilobite Kasachstania Maksimova, 1972, previously reported from the Lower Devonian of Kazakhstan and North America (USA) and the upper Silurian–Lower Devonian of South America (Bolivia and Argentina), is revised. Kasachstania kasachstanica (Balashova in Maksimova,1968) and K. septicostata (Maksimova, 1968) are regarded as junior synonyms of the type species K. saryarkensis (Maksimova, 1960), all from the Lower Devonian of the type locality in central Kazakhstan (northern Balkhash). On the basis of a new diagnosis, K. ulrichi ulrichi (Delo, 1940) from the Emsian of the United States, K. ulrichi asiatica (Maksimova, 1968), K. pristina (Maksimova, 1968), and K. alperovichi Pour et al., 2019, from the Lower Devonian of Kazakhstan, K. andii (Kozłowski, 1923) from the upper Silurian–Lower Devonian of Bolivia, and K. gerardoi Edgecombe and Ramsköld, 1994, from the upper Silurian–Lower Devonian of Bolivia and Argentina are excluded from Kasachstania. This genus, represented only by K. saryarkensis and K. kiikbaica (Maksimova, 1968), is restricted to the Lower Devonian of central Kazakhstan, corresponding to the Balkhash–Mongolo–Okhotsk province in the paleobiogeographic context of the Old World Realm, instead of being nearly cosmopolitan as previously considered. In addition, we provide some remarks about Saryarkella Maksimova, 1978b, a monospecific dalmanitid genus largely overlooked although valid from the Emsian of the same area in central Kazakhstan.

The Cincinnatian (Katian) of the Cincinnati Tri-State area is widely regarded as one of the most fossiliferous sections known (Meyer and Davis, 2009). Echinoderms from these strata include well-described asteroids, crinoids, cyclocystoids, edrioasteroids, glyptocystoids, mitrates, and ophiuroids. John Pope discovered a partially articulated echinoderm in float from the Fairview Formation that does not correspond to any known Cincinnatian echinoderm. Although mentioned in Ubaghs (1966, as a presumable personal communication from Pope, 1960), Haude and Langenstrassen (1976), Reich (2001), and Reich and Haude (2004), this specimen at the Cincinnati Museum Center (CMCPIP 51316) has neither been described nor illustrated; yet, these authors attributed it to Volchovia Hecker, 1938 in the Class Ophiocistioidea. Questions swirl around this fossil: what is its complete morphology; does it belong to Volchovia; whether or not it can be assigned to Volchovia, is it an ophiocistioid? The first step to understand this enigmatic echinoderm is to illustrate and describe the specimen, which is the objective of this note.

Gastropods are rare fossils in the Cambrian of Wisconsin. They are usually small and flattened. During the summer of 1978, while collecting trilobites along the western side of the state, I discovered a new gastropod in the Crepicephalus zone (as defined by Twenhofel, Raasch, and Thwaites, 1935; Nelson, 1951). It is a three-dimensional fossil represented by external mold and steinkern. This was the only gastropod uncovered during the splitting of over 200 kilograms of sandstone, which also yielded hundreds of trilobite cranidia and pygidia.

During recent stratigraphical and micropaleontological investigations of the Gulupu section in Tüna, Yadong, of the Eocene Zhepure Formation, numerous holoplanktonic mollusks (pteropods) were recovered. Four species, assignable to two genera of pteropods (including Limacina yadongensis new species) were systematically described and illustrated, and a gastropod-bivalve biofacies was identified. This is the first report of Eocene (Ypresian) pteropods in southern Tibet; the same stratum also yields many other neritic faunas. The data presented in this study suggest that a semi-closed restricted gulf in the Tüna area existed and the occurrence of pteropods in Tüna may indicate transport from more open, deep water by oceanic currents during early Eocene. Based on the analysis of paleogeographical distribution of pteropods, it indicates that a Tethys seaway existed during the early Eocene (Ypresian).

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Pandorinellina? boucoti (Klapper) is based on material from the Lochkovian–Pragian (Devonian) section at Royal Creek, Yukon Territory, Canada, where it is found with species of the pesavis and sulcatus Zones. The species is also a rare element in the late Lochkovian–early Pragian faunas in the Toquima Range, central Nevada, where it is found within the same zones. Pandorinellina? boucoti has been recovered from 17 beds in sequence at the IK IV section in the McMonnigal Limestone and shows a morphologic change from a Pa element with a simple blade, small lateral lobes, and an enlarged triangular anterior denticle to a Pa element with ornamented pillars surmounting both platform lobes. The simple blade form is present in beds IK IV 21–16. The next overlying bed yields specimens with a single pillar-like enlargement of the larger platform lobe and a slight swelling on the smaller platform lobe. The following beds (IK IV 14–6) have only morphotypes with the pillar-like enlargement on both platform lobes.

This morphologic change effectively divides the upper pesavis Zone into two segments in the IK IV section. The rarity of this species, however, will probably limit the usefulness of the lineage in refined biostratigraphy and the sequence of morphotypes needs to be verified in other areas. Nevertheless, where present, P.? boucoti should improve the accuracy of correlation in the late Lochkovian and early Pragian.