158 Miscellaneous. 



pointed. The leaves broad oval, not narrowed towards the emargi- 

 nate apex ; the primary veins nine on each side the central one ; on 

 the back of the leaf convex, soft ; secondary veins concave on both 

 sides— J. De C. S. 



ON THE STRUCTURE OF THE BELEMNITE. 



To the Editoi's of the Annals of Natural History. 



Gentlemen, — When a disputant aifirms a statement * most em- 

 phatically,' it may be suspected that the emphasis is added to supply 

 the want of inherent truth. This is the case with Dr. Mantell when 

 he so affirms that the " phragmocone is common to numerous genera 

 of Cephalopods," — a statement which is made to appear true only 

 by attaching to the term ' phragmocone ' a meaning peculiar to the 

 asserter. A * conical chambered siphunculated shell ' is no doubt com- 

 mon to numerous genera of Cephalopods : before Owen's anatomy of 

 the Nautilus, Belemnites, and Spirula, it was deemed to characterize 

 all that section of the class which Cuvier grouped together under the 

 wide Linnsean term of Nautilus, and with which the " Sijihonifera " 

 of Ferussac and D'Orbigny is synonymous. The term ' phragmo- 

 cone ' was first proposed by Professor Owen, and applied by him to 

 a particular modification of the ' conical chambered siphunculated 

 shell ' ; to that viz. in which the cone is short and straight, the 

 chambers very shallow, and rapidly enlarging, uniformly concave to- 

 wards the outlet, with the siphuncle marginal and ventral, and the 

 whole invested by a partly horny, partly calcareous layer continuous 

 with the sheath protecting the more advanced parts of the Belemnite 

 (Phil. Trans. 1844,j)p. 68, 69). This modification of the 'conical 

 chambered siphunculated shell ' is common to all the subgenera into 

 which the ' Belemnites ' of Cuvier have since been divided, and it is 

 'peculiar' to them. 



The most variable and therefore least important part of their com- 

 plex shell is the ' dart,' ' guard,' or ' osselet ' ; its different forms and 

 proportions afford, indeed, the characters of most of the species, and 

 in the Bel. brevissitna, Duv., e. g., it is reduced to the size of the 

 similarly solid calcareous terminal mucro of the shell of Beloptera, 

 Sepia, &c., to which, according to Cuvier, Buckland, and other emi- 

 nent naturalists, it is answerable. So much, therefore, for Dr. Man- 

 tell' s other affirmation that the part which he chooses to call ' osselet ' 

 is the essential part or character of the Belemnite. I shall not tres- 

 pass on your space by any notice of Dr. Mantell' s views of the value 

 of Professor Owen's researches on the extinct Cephalopods possessing 

 the ' phragmacone,' or of my own opinion of the influence of the Pro- 

 fessor's works in general on the progress of Comparative Anatomy : 

 and I limit myself to a single sample of the nature of the discoveries 

 to which Dr. Mantell vaunts his peculiar claims. The part, e. g., 

 which he calls the capsule or sheath is the part so called by Buck- 

 land, together with other parts subsequently pointed out by Owen. 

 The author of the 6th Bridgewater Treatise (p. 3/2) describes — 

 " A conical thin horny sheath, or cup, commencing from the base of 



