46 CARBONIFEROUS LAMELLIBRANCHIATA. 



1879. In the ' Bulletin of the United States Geological Survey of the 

 Territories,' vol. v, No. 2, 1879, C. A. White, in his "Remarks on certain 

 Carboniferous Fossils from Colorado, Arizona, &c.," pp. 216, 217, describes as 

 new — 



Nuculana obesa. 

 Nucula perumhonata. 



Allorisma ? Gilherti. 

 (All from Northern Arizona.) 



In 1879 the Explanation of Sheet 31 of ' Memoirs of the Greological Survey of 

 Scotland' was published, with an Appendix by Mr. R. Etheridge, jun., on the 

 localities of the fossils found in the area contained in the map. At p. 80 are 

 "Notes on some of the Species," three new species of Carboniferous Lamelli- 

 branchiata being described : 



Aviculopecten, sp. ind. 



— suhanisotus. 



Anthracoptera tumida. 



1881. Mr. Robert Etheridge, sen., gave his presidential address to the 

 Geological Society " On the Analysis and Distribution of the British Palasozoic 

 Fossils " in 1881, subsequently published in No. 146, vol. xxxvii, of the 

 ' Quarterly Journal.' At page ccxvi he states that the Monomyaria " and the 

 Dimyaria united number no less than 54 genera and 415* species." Ten genera, 

 with 179 species, belong to the Monomyaria, 103 of which are referred to Aviculo- 

 pecten ; and 43 genera, with 245 species, are included in the Dimyaria. 



Tables are given showing the number of species in several genera of Mono- and 

 Dimyarians which occur in England, Scotland, Ireland, Belgium, and America, 

 and the number of genera and species occurring in certain subdivisions of the 

 Carboniferous beds are also indicated. 



1882. On the 13tli January, 1880, Mr. John Young read his " Notes on some 

 Carboniferous Lamellibranchs, their Mode of Occurrence and observed Shell- 

 structure," which were published in vol. vi of the ' Transactions of the Geological 

 Society of Glasgow,' p. 223. He records the following genera as possessing a 

 prismatic cellular structure in the shell : Anthracoptera, Pinna, Pteroniles, 

 Posidonomya, and Myalina. He says, " So far as I bave examined my 

 Carboniferous Lamellibranchs, I find that this prismatic cellular structure is con- 

 fined to shells belonging to the AvicuUdse, or wing-shells, and the Mijtilidce, or 



* On the next page this figure is more correctly given aa 424, 179 + 2-45. 



