Pahvozo'ic Bivalved Entomostraca. 343 



both are hig-lohed (" female ") forms of B. Maccoyiana^ 

 Jones ; but we cannot agree with him in this proposition. 

 His suggestion that B. prot,uberans^ Boll, is the hig-lohed 

 form of B. Klcedeni, M'Coy, is highly probable. We see the 

 same condition in Heiclenhain's pi. i. fig. 14, which is wrongly 

 referred to B. tuherculata, as pointed out by Krause (op. cit. 

 p. 32), who doubts, however, its being B. Klcedeni. 



In his description of B. grandis (1880, p. 138), Dr. Kol- 

 modin regards the big lobe there present as being 'posterior ; 

 but it may well be antero-ventral, as we have regarded it in 

 other such forms. In B. grandis it bears on its middle a low 

 process, hollowed out at the top like an oval-lipped hollow 

 wart. This specimen and the one described and figured by 

 Boll as B. elegans (1862, p. 135, fig. 10) are both imperfect 

 (probably having been thin-shelled), and yet appear to have 

 much in common — in their outlines, in the relative size and 

 position of the central lobe, and in the oval outline of the 

 exaggerated lobe, Avhich is said to be neatly granulated in 

 Kolmodin's, and cross-cut with stria;, bounding minute inter- 

 mediate elevations, in Boll's specimen, the meshes longest 

 with the long axis of the lobe. The exceptional size of the 

 front lobe and the general granulation * of the surface make 

 the chief differences. 



The large collections of O^tracoda made of late years by 

 Messrs. John Smith f and G. R. Vine J from the Upper- 

 Silurian § shales of Shropshire having been confided to us 

 for description, we have had a good opportunity of extending 

 our knowledge of the Beyrichice. Mr. C. D. Sherborn has 

 effectively aided us in our work. 



By careful working Mr. Vine in 1881 had picked out of 

 the Upper-Silurian shales supplied by Mr. G. Maw, F.G.S. ||, 

 more than 60,000 specimens of the remains of Actinozoa, 

 Echinodermata, Annelida, Polyzoa, Brachiopoda, Trilobita, 

 and Entomostraca. Of the Polyzoa and Annelida he supplied 

 descriptions in the Quart. Journ. Geol. Soc. vol. xxxviii. 1882, 

 pp. 44 &c., and ihid. pp. 377 &c. ; and lists of the others 

 were given at the same time (see ihid. pp. 47-49). 



His collection of the Entomostraca comprised many hun- 

 dreds of specimens, and he commenced describing and 



* It is difficult to determine under some microscopes whether we have 

 granules or pits. 



t Geol. Mag. dec. ii. vol. viii. 1881, pp. 70-75. 



j Quart. Journ. Geol. Soc. vol. xxxviii. 1882, pp. 44 and 48. 



§ " Upper Silurian " of Murchison and the Geological Survey, but 

 '' Silurian ' of tlie Cambridge school of geologists. 



II See the paper by Davidson and Maw, Geol. Mag. dec, ii. vol. viii. 

 1881, pp. 100-10(3. 



