BRITISH FOSSILS. 7 



In the first place he ,gives a clear view of the structure of Beleni- 

 nites in general, repeating and extending his previous statements, and 

 more especially denning his opinion as to the meaning of the conothecal 

 stria?. 



"As the stria? of growth represent the successive openings of shells, 

 one is always enabled to form an exact idea of the form of a shell at 

 any stage of its growth, when the whole length of these striae is fol- 

 lowed out. so that an exact idea of the form of the opening of the cono- 

 theca (test alveolaire) of a Belemnite may be formed by following one 

 of the lines of growth.'* 



Volte gives a restoration of the Belemnite shell constructed upon 

 this principle in the third figure of the third plate of the work cited. 



The Liassic and Oolitic pens are, for M. Voltz, the pro-ostraca of 

 Be lemnites ; but as these Belemnites are unknown, he proposes for 

 them the new generic name of Belope his. In anticipation of obvious 

 objections, M. Voltz writes : 



" It might be supposed that the Belopeltes belong to some other 

 genus of Cephalopods than Belemnites, or than any other known form 

 of Acetabulifera ; and the shell of which, though without a guard, had 

 much analogy with the alveolar test [conotheca] of the Belemuite. 

 But then one would ask why these Belopeltes are always incomplete 

 at their apices, a fact which is fully explained, and, so to speak, be- 

 comes a necessity, when these fossils are referred to Belemnites. It 

 would also be necessary to explain why no fossils we ever found which 

 can be referred to the apex of Belopeltis, and why, lastly, fossils are 

 never met with appertaining to the dorsal lobe of the alveolar test of 

 Belemnites : a very much elongated lobe, the existence of which in 

 entire and uninjured Belemnites cannot be doubted by any one who 

 has cai-efully examined the strife of growth of the alveolar test [cono- 

 theca] of the Belemnites." L.c., p. 21. 



And further, in his " Observations Supplernentaires " (l.c. p. 31) : 



M. Buckland gives, on his Plates 44' and 44", figures representing 

 fragments of Belemnites found &t Lyme Regis and still containing the 

 ink-bag. The figure 7, Plate 44', represents Belemnites ovalis with its 

 ink-bag. 



" It is to be regretted that M. Buckland has not published a figure of 

 the counterpart of this specimen ; for M. Agassiz, who studied this very 

 important fossil in 1834 or 1835, and who discussed it at length with 

 M. Buckland, says, in the German translation of the Bridgewater 

 Treatise, that the counterpart of the fossil exhibits the dorsal region 

 of the alveolus with striae similar to those which are seen in Plates 28, 

 29, and 30 of this work,* so that not the smallest doubt could be enter- 

 tained as to the justice of the union of Belopeltis with Belemnites, a 

 union the necessity of which was made obvious to my friend, M. 

 Agassiz, by his first inspection of the fossil. 



" M. Buckland states in his work that the specimen presents a 

 nacreous test showing transverse and waved stria?. M. Agassiz says, 

 on the other hand, that he does not comprehend this explanation, and 

 that these striae are the traces of the sutures of the septa with the 

 alveolar cone. The mere inspection of the figure suggests the same 

 idea, for these stria? appear to be more marked than simple striae 

 of growth would be, and they are placed at relative distances which 

 correspond well to the intervals between the alveoli of Belemnites, and 

 which are too great to be striae of growth. If this be the case, it 



Pen and ink-bags of Loligo " are represented on these plate*. 



