SEPIOPHORA. 



8 79 



layer, which invests the conical phragmacone. The members of 

 this family are confined to the Upper Trias and the Jurassic rocks, 

 and the principal genus is Belem?ioteuthis (fig. 810) itself. In the 

 Oxford Clay, specimens of Belemnoteuthis have been found in which 

 the outline of the soft parts has been more or less perfectly pre- 

 served. From these it is known that the animal had eight arms, 

 with two " tentacles," furnished with horny hooks. The hinder end 

 of the body was furnished with terminal fins ; and there was a large 

 ink-sac situated a little in front of the phragmacone. The phragma- 

 cone itself seems to have reached to nearly one-third of the length 

 of the body. 



Section B. Sepiophora. 



In this section of the Decapods the skeleton is internal and is 

 calcareous, consisting of a well-developed " pro-ostracum," termin- 



er 



m 



Fig. 810. — Restoration of Belemno- 

 teuthis, from the Oxford Clay. 



Fig. 811. — Side-view (a) and ventral view 

 (b) of the shell of Sepia Orbignyana. p, 

 "Pro-ostracum"; m, Mucro, hollowed out 

 in front for the rudimentary phragmacone ; 

 d, Dorsal side of the shell ; v, Ventral side. 

 (After D'Orbigny.) 



ating posteriorly in a rudimentary phragmacone and rostrum. No 

 siphuncle is developed. 



The type of this section is the existing genus Sepia, in which the 

 shell ("sepion" or " sepiostaire ") consists of an elongated, oval, 

 calcareous "pro-ostracum" (fig. 811,/), which is rounded in front, 



