602 LECTURE XXIII. 



Stratified masses called diluvial. The attempt to conceive or calculate 

 the period of time which must have elapsed since the Belemnites were 

 thus embalmed, baffles and awes the imagination. 



A second less complete, but highly instructive, specimen of the 

 same kind of Belemnite*, exhibited the funnel, a great proportion of 

 the muscular parts of the mantle, and the remains of two lateral fins, 

 the ink-bladder and duct, and a considerable portion of the chambered 

 cone. The two fins {fig. 218,//) present the form of flattened 

 transversely striated fibrous masses with their free border entire and 

 rounded. They are situated on each side of the visceral cavity, and 

 demonstrate the accuracy of M. Duval's objection to their position in 

 the previous conjectural restorations. A large tract of the grey 

 fibrous substance, running parallel with and on one side of the re- 

 mains of the head, indicates the position of the infundibulum, and is 

 terminated by a concave truncation. At the middle of the visceral 

 mass at the interval of the two lateral fins, there lies a compressed 

 body of a horny texture and somewhat bilobed form, on which may 

 be clearly distinguished striae passing outwards in opposite directions 

 from a middle line, and diverging from each other in their course, 

 which resembles that of the fibres of the digastric muscle in the 

 gizzards of the Cephalopods : this apparent remnant of the stomach 

 lies anterior to the ink-bladder. There is a strong negative evidence 

 that the Belemnite possessed horny mandibles like the other naked 

 Cephalopods, since no calcareous ones, called Rhyncholites, have been 

 discovered associated with these remains. The cephalic arms, which 

 are preserved in a third specimen with the contour of the large ses- 

 sile eyes, belong to the normal series, and were eight in number : 

 they were provided, not with simple acetabula, but with a double 

 alternate series of slender elongated horny hooks, as in the genus of 

 existing Calamaries, called Onychoteuthis. Each arm seems to have 

 been provided with from twelve to twenty pairs of these hooks. They 

 were doubtless developments of the horny hoop which encircles the 

 central process of the acetabulum, as in the modern Onychoteuthides ; 

 but in the position of the pallial fins, the Belemnite resembled the 

 Sepiola. The traces of the superadded pair of tentacula are some- 

 what doubtful. 



The modern decapodous Cephalopod, which most nearly resembles 

 the Belemnite in the structure of its internal shell, is the Sepia, or 



* CCCXCVI. pi. iii. For these apparently guardless species, first submitted to 

 me by Mr. C. Pearce, I suggested the subgeneric name of Bekmnoteuthis, which he 

 adopted. But the importance of the subsequently discovered specimens, with the 

 soft parts, for the elucidation of the nature of the Belemnitidce, is in no way 

 affected hy subgeneric nomenclature, so long as naturalists concur in regarding the 

 *' phragmocone " as the essential part of the Belemnitic shell. 



