T 



86 KBroRT— 1884. 



was fi'oni the Lower Silurian of Pcinvliapple Burn, near Girvan, Ayr- 

 shire ; and we Avish to give it the name of IHpterocaris Etheridyel, in com- 

 pliment to Mr. R. Etheridge, inn., who has worked so well among the 

 palfioozoic! Phyllopods and other fossils. 



Whether or no the hinder cleft in Bipterocaris was ever occupied by 

 a triangular piece, lost after death, we cannot say. No direct evidence 

 supports the idea that there was a portion of the est filling in this 

 posterior notch ; but the elongate triangle define by the radiating 

 furi'ows in Pholadocaris Lecii, and by ridges (P) vii Ph. sp. (F. A. 

 Roemer's ' Aptychus '), seems to bo an analogous feature. On the other 

 band, the posf orior notch in Dijiterocaris may have had reference to the pro- 

 j trusion of the abdominal somites, as suggested by ^Ir. J. M. Clarke, ' Amer. 



j Journ. Sci.' 3, vol. xxv. p. 124, Mr. Clarke, luc. cit., considers it pro- 



1 bable that the anterior cloft was also permanently open, for the convenient 



j protrusion of the cephalic appendages ; bnt a'.tilogy with other Phijllo- 



\ ntrida, and especially the abi u[>t termination ol' the concentric lines of 



{ growth on the edges of the notch (as if the lines were continued on a 



I cephalic piece, as in allied forms), are our reasons for retaining the 



views we have already expressed. 



DlI'TEROCARIS. 



Dipterocar^s jtes-cervrc Without Goniatites. Upper Devonian, New York State. 



„ ri'tmta With „ „ ,, Hartz. 



„ proBne ~j ("■.!>. New York State. 



„ pcniKP-dcrddU '. Witliont „ J „ „ „ „ 



„ Mheridgci J [_ Lower Silurian, Scotlanil. 



t VIII. PinuocARts, Barrandc, 1872. PL bohemica, Barr. ' Syst. Silur, 



Boheme,' vol. i. Supplem. p. 4G1, pi. 2'), figs, 25, 20, 



A single specimen (a cast) of this interesting fonn has been carefully 

 described by M, J, Barrande in detail. Its apparent relationship to 

 Apiychopsis and other fossil Phyllopods is pointed out ; its anterior, 

 triangular, apparently fixed, rostral piece, and its open and deep posterior 

 cleft, are described and figui'cd, together with the radiate ornament of 

 the lateral pieces of this cast. The fossil is flat. Broadly obovato in 

 outline (outside the notch). Length 12 mn: vidth about 12 mm. 



In general shape Pferocaris corresponds Wi... Biptc ocaris, and indeed, 

 exhibits the cephalic or rostral piece, which has been lost from the other 

 specimens known. The ornamentation, however, aa preserved on the 

 cast (apparently of the inner or lower side) is peculiar, being stria; 

 radiating from a straight line which reaches along the greatest length of 

 each wing or lateral piece, and is parallel to the median line of the 

 isthmus ; or rather the stria) look as if they would converge centrally on 

 the isthmus, if they were not intcrru'^ted by the longitudinal line on each 

 wing. In Bipterocaris the ornamental lines are concentric with the 

 isthmus. 



From the quartzite of D d2. (Lower Silurian = Llandeilo and 

 Caradoc) at Mount Drabow, with Caryon hohemicum, Zono::ne, 2 spp., 

 and Cytheropsis testis. 



The last-mentioned foF.sil is an internal cast apparently, as M. 



• Barrande suggests, of some half-shut Entomostraean bivalve ; side-view 



elongate, subelliptical, with a straight dorsal edge and neatly roundeel 



