SILUEIAN OSTRACODA EEOM NOETH AMEEICA, ETC. 537 



of some fossils previously collected by M. Dumont from, the fossi- 

 liferous, Devonian, schistose rocks at Arnaut Kjoi, on the Bosphorus, 

 and preserved in the Museum of the University of Liege. M. De- 

 walque, the Director of that Museum, has very kindly allowed me 

 to examine and describe the BeyricJiia noticed by Dr. Perd. Eomer 

 in the memoir referred to above, the tv^o little figures given in 1863 

 not being sufficient for the determination of the species. 



It is a somewhat worn, ferruginous cast of a left valve in a 

 schistose sandy mudstone, containing also casts of the remains of 

 Brachiopods and Encrinites. The valve has been squeezed, length- 

 ened, and considerably distorted, as is especially shown by its pro- 

 file, fig. 1 h. Apparently it possessed three lobes ; two of them joined 

 together ventrally, thus making one curved lobe ; the other being 

 separate and close to one end of the valve. In the cast, however, 

 the horseshoe lobe (consisting of the large pyriform posterior or 

 gigot lobe, and the middle lobe, united) has been pushed far on over 

 the middle of the valve, closely approaching the separate (anterior) 

 lobe, and leaving a wide, sloping, blank area behind. 



For comparison, fig. 2, B. devonica, from Devonshire (left valve ; 

 Geol. Mag. loc. cit. fig. 3, of the same natural size, but x 6 diam. 

 instead of x 12), is here introduced ; also fig. 3, which is a squeezed 

 modification of the same species (right valve ; ihicl. fig. 5, nat. size 

 3 mm. and X 6 diam.), in which the curved junction of the big and 

 middle lobes is broken, and the anterior lobe somewhat lessened in 

 size. Taking fig. 2 «, which was chosen from among numerous 

 more or less modified individuals in the same rock, to represent a 

 valve (from Devonshire) in its natural condition, we may readily 

 take fig. 1 (from the Bosphorus) as a distorted example of a similar 

 form ; and I venture to suggest that it may belong to the same 

 species. 



At page 517 of his Memoir mentioned above, Dr. Perd. Eomer 

 refers these fossiliferous rocks of the Bosphorus to the Middle and 

 Upper Devonian ; but M. de Verneuil (Bullet. Soc, Geol. Prance, 

 ser. 2, vol. xxi. (1864), pp. 147-155) regarded them as of Lower- 

 Devonian age. In his memoir on the Geological Conditions of the 

 Eastern part of European Turkey (Jahrb. der k.-k. geol. Eeichs- 

 anstalt, vol. xx. 1870), Dr. Perd. von Hochstetter referred them on 

 palseontological grounds to the horizon of the Lower-Devonian beds 

 of Western Europe, noting also that they contain some few Upper- 

 Silurian fossils. Mr. W. E. Swan, also, in the Quart. Journ. Geol. 

 Soc. vol. XX. 1864, p. 115, treats of them as being on a level with 

 the Lower Devonian of the Ehine and probably of Plymouth and 

 Ogwell in Devonshire. 



3. BeYEICHIA STJBQTJADEATA, Sp. UOV. (PI. XX. fig. 4.) 



Length 1*3 mm. ; height '93 mm. 



A hollow cast of the outside of a Beyrichian valve gives, in re- 

 verse, the shape and contour shown in fig. 4. This approximates in 

 some degree to B. devonica (figs. 1, 2, 3), having an isolated anterior 

 lobe and two thick lobes united by a ventral curve. Its relative 



