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A critical assessment of the use of the micrometric formula in classifying fenestrate cryptostomes shows that although the device may be of some use as an aid to description and as a means of indexing species, it is an ineffective basis for structural comparisons. The method employed in making such comparisons is also unsound. Nevertheless, taxonomic conclusions are commonly drawn from them, and a result of this is an unreasonable increase in the number of recognized species.

• Read more about The micrometric formula and the classification of fenestrate cryptostomes

Exceptionally well-preserved specimens of Caryocaris from Alaska and the Great Basin show a peculiar shell enrolment; several other important skeletal details are described for the first time. In the light of this new material, Ruedemann's types that are the basis for his reconstructions of Caryocaris are re-examined. Finally, a review of the stratigraphic range of Caryocaris leads to the conclusion that none of its reported Silurian species are definitely Caryocaris.

• Read more about Morphology and stratigraphic range of the phyllocarid crustacean Caryocaris from Alaska and the Great Basin

Silicifled wood from the sands of the Woolwich Series (Landenian) at Herne Bay, Kent, is described as Edenoxylon aemulum sp. nov. (Anacardiaceae). The specimen closely resembles wood described from the Lower Eocene Green River Formation of Wyoming, U.S.A., as Edenoxylon parviareolatum Kruse. The character of the wood is essentially that of a tropical type with no strongly marked seasonal increments in its radial growth.

• Read more about Fossil wood of Anacardiaceae from the British Eocene

Parachonetes is proposed as a new chonetid genus with Chonetes macrostriata Walcott from Nevada as its type species. It is thought to have been derived from the protochonetid genus Eccentricosta. Barrande's species Chonetes verneuili is assigned to Parachonetes as are two named species from south-eastern Australia. Parachonetes is absent in eastern North America, but is represented in Nevada, the Canadian Arctic, Novaya Zemlya, the Ural Mountains, Central Asia, south-eastern Asia, Czechoslovakia, and in south-eastern Australia.

• Read more about Parachonetes, a new Lower and Middle Devonian brachiopod genus

A description is given of a variety of borings and signs of predation which occurred either during the life or after the death of some Visean brachiopods. These structures, thought to have been produced by sponges, bryozoans, gastropods, and fish are of interest as indicators of environment and of the type of death assemblage met within these rocks.

• Read more about Predation and shell damage in a Viséan brachiopod fauna

Both smooth and strongly ribbed stricklandiid brachiopods occur together in early Upper Llandovery beds(Ci-C3)at Presteigne. Aenigmastricklandia contorta gen. et sp. nov. is proposed for the ribbed species, while the smooth species is assigned to Stricklandia lens aff. progressa Williams. Aenigmastricklandia appears to be an early ribbed offshoot of the main stricklandiid line; a parallel development is seen in Costistricklandia, which appeared toward the end of Upper Llandovery time (C6-C6).

• Read more about Unusual stricklandiid brachiopods from the Upper Llandovery beds near Presteigne, Radnorshire

Acritarchs from the Lower Triassic of Western Australia are examined with an electron microscope. As they are almost opaque to the electron beam, a modified replication technique is used to elucidate the fine structure of their tests. This examination is shown to be of taxonomic value, and a new variant is described.

• Read more about The fine structure of some Lower Triassic acritarchs

A new odontopleurid genus Isoprusia (type /. mydlakia sp. nov.) is described and assigned to the subfamily Miraspidinae R. and E. Richter, 1917. The new genus includes Odontopleura laportei Hawle and Corda, Acidaspis Ursula Barrande, ? A. sperata Barrande, A. (Ceratocephala) sandbergeri R. and E. Richter, Orpkanaspis cornuticauda Erben, and Koneprusia pennata Lutke. Features of the pygidium of the new genus enable it to be distinguished from Koneprusia Prantl and Pribyl 1949, the type material of which cannot be traced.

• Read more about A new odontopleurid trilobite genus from the Devonian of Bohemia

Neomicroceras commune gen. et sp. nov., family Eoderoceratidae, is described and figured from the Raricostatum Zone of the British Lower Lias. The genus Paracymbites Trueman and Williams 1927, from the same zone, is revised from the original types and other material, and placed in the family Oxynoticeratidae.

• Read more about The Lower Liassic ammonites Neomicroceras gen. nov. and Paracymbites

Albaillella pennata sp. nov. and Popofskyellum undulatum Deflandre are described from calcareous concretions at the horizon of the goniatite Reticuloceras paucicrenulatum Bisat and Hudson. The diagnosis of the genus Albaillella is emended. It is suggested that A. pennata and P. undulatum may possibly have been favoured by depths of water greater than those necessary for the proliferation of Namurian spumelline Radiolaria, and that depths favouring these two forms may have been attained only rarely during the deposition of Namurian goniatite bands in Derbyshire and Staffordshire.

• Read more about Radiolaria from the Namurian of Derbyshire