958 PROF. OWEN ON THE [Nov. 19, 



to the correctness of the position assigned by me to the soft parts 

 of Nautilus in the shell 1 ; but the sole reason assigned by Stoliczka 

 for adhering to Von Buch's view of the position of the shell and his 

 consequent denomination of its parts is the following: — "Our de- 

 scriptions are of the shell {Am. testa), not of the animal which was 

 living in it, and which we know not" 2 . 



We shall never know the organization of that animal ex visu. 

 But there are, in respect of the Ammonite as of most extinct ani- 

 mals, other sources of knowledge in kind and degree sufficient to 

 decide such a question as the relations of soft parts to shell in a 

 Molluscous species. 



With regard to those relations in Nautilus I may merely cite the 

 subjoined works on its anatomy confirmatory in the main of my 

 own, and fully so in regard to the relative position of the soft parts 

 to the shell 3 . 



the accomplished Professor of Comparative Anatomy in University College, 

 Dr. Egbert E. Grant, F.E.S., and begat a general belief, in 1833, that I had 

 placed the animal of the Pearly Nautilus in a position the reverse of the real 

 one, in the 'Memoir' of 1832. In the report of the Lecture on the Shells of 

 the Cephalopoda, given in the ' Lancet,' vol. i. 1833, with the sanction and 

 revision of the Professor, Dr. Grant remarks : — 



" The exact position of the animal in the recent Nautili, Spirilla, and other 

 polythalamous spiral shells, although important in the interpretation of the 

 fossil forms, has not yet been satisfactorily observed by naturalists. In our 

 present uncertainty, therefore, regarding the position of the living Cephalopods 

 in these convoluted shells, we can only be guided by analogy." 



That which guided Dr. Grant to his conclusion he illustrated by figures of 

 sections of the external shell of Nautilus and of the internal shell of Sepia (p. 

 506), and explained them as follows. Comparing the layers of the "cuttle- 

 bone " to the septa of the Nautilus shell, he states : — " These layers begin in the 

 Sepia by forming a small hollow shell, which receives into its interior another 

 hollow shell; this receives within it a third and a fourth hollow shell; and so 

 they go on in the first stages of its growth. If these cones continued thus to 

 extend outwards, and with an oblique direction, turning on the same vertical 

 plane, the3 r would have formed a convoluted suborbicular shell, like that of the 

 Ammonite or the Nautilus. Where, then, in this so convoluted shell of the 

 Sepia, would have been the convex outer border of the shell, or the upper lip, 

 with relation to the body of the Sepia ? The Sepia would have looked for- 

 wards over the spire from the last-formed chamber, keeping the exterior convex 

 part of the chamber" (answering to B in fig. 3) "or the upper lipextending across 

 its back, as in all other known orbicular shells of Pteropodous and Gusteropo- 

 dous Mollusca." (P. 509.) 



1 Memoir, ut supra, pp. 12, 44, pi. i. 



a Op. cit. p. 44. So, likewise, affirms a later writer : — " We have only the 

 shells preserved to us. We know nothing of the animals." — H. Woodward, 

 Geol. Mag. vol. v. p. 497. 



As well might it be affirmed of Anoplotherium, e. g. : — " It must always be 

 borne in mind, when arguing from these early fossil remains, that we have only 

 the skeleton preserved to us. We know nothing of the soft parts." 



3 Valenciennes, M. A. "Nouvelles Eecherches sur le Nautile ilambo 

 (Nautilus pompilius, ~Lam.)," Archives du Museum d'Histoire Naturelle, Paris, 

 4to, tome ii., 1841, p. 275, pis. viii., ix., x. 



Van der Hoeven, J. "Contributions to the Knowledge of the Animal of 

 Nautilus pompilius," Trans. Zool. Soe. vol. iv. p. 21, pis. 5, 6, 7, 8. 



Vrolik, W. " Lettre sur quelqucs points de l'organisation de l'animal du 

 Nautile flambe,'' Memoires de la Soc. Liuneenne de Normandie, torn, x., 4to, 

 1855, pp. 1-18, pis. i. and ii. 



