[5] 



Figs. 22 & 23. /. tenuis Mant., Eed Chalk : 22, left valve ; 23, anterior. 24-26. 

 I. etheridgei Woods, Holaster-suhglohosus Zone : 24, left valve ; 

 25, anterior ; 26, right valve. All @ two-thirds of the natural size. 



II. Species connected with Inocebamus neocomiensis 



We may now consider the species which are believed to be 

 connected with 1. neocomiensis, the distribution and relationship of 

 which are shown in the accompanying diagram (B, p. 6). 



/. neocomiensis d'Orb. (fig. 27, p. 8) is found in the Lower Green- 

 sand, and a similar form (/. ewaldi Schliit.) occurs in the Aptian of 

 North Germany. 



/. anglicus Woods (figs. 28, 29, 56, & 57)^ occurs in the Gault, the 

 Eed Chalk, and the Upper Greensand, and appears to have arisen 

 from a form of the type of /. neocomiensis. They agree in the 

 general shape of the shell and in the type of ornamentation ; but 

 in /. anglicus the posterior part of the shell is more compressed, 

 while the part ventral to the umbones is more convex than in 

 /. neocomiensis ; also in the former the ventral curvature of the 

 ribs is sharper than in the latter. From /. anglicus two species 

 seem to have arisen — /. pictus and /. crippsi. 



^ H. Woods, op. cit. pi. xlv, figs. 8-10, & text-fig. 29. 



