240 
ZOOLOGICAL LITERATURE. 
the author concludes that tlie chambered and siphonated cha- 
racter of some cephalopod shells is entirely due to the periodic 
development of the organs for reproduction, — the formation of 
the spaces for chambers being the result of enlargement of the 
ovaries and testes, and the formation of the siphuncles a ne- 
cessary result of their collapse after the contents of those organs 
are extruded. 
Hensen, Von. Ueber das Auge einiger Cephalopoden. [On 
the eye of some Cephalopods.] Zeitschr. Wiss. Zool. xv. 
pp. 155-242, pi. 12-21. (Abstract in Ann. Sc. Nat. iv. 
pp. 374-381.) 
Keeerstein, W. Beitrage zur Anatomic des Nautilus pom- 
pilius. [Contributions to the anatomy of Nautilus pompi- 
lias.'] Nachricht. K. Gesellsch. Wiss. Gottingen, 1865, 
August, pp. 355-375, with six plates. 
A careful description of the external and internal parts of a 
female specimen. 
Aryonauta. Mr. G. B. Sowerby (Thesaurus, part xxiii. pp. 263 & 264, pis. 
267 & 258) admits and figures six species : — A. argo (L.), tuberculosa (liam.), 
nodosa (Solander), gondola (Dillw.), hians (Dillw.), oioenii (Adams & lieeve), 
and gvuneri (Dunker). The Recorder does not think that the ear-like pro- 
longations at the sides of the mouth are of specific value, having observed 
them more or less developed and entirely wanting in specimens of A. argo, 
which in other respects were quite identical j the same variation occurs in 
specimens of A, tuberculosa ; therefore this character does not appear to be 
sufiicient for the specific distinction of A. gondola and A. hians. 
PTEROPODA. 
Spirialis recurvirostra, sp. n., Costa, Rendic. Accad. Sc. fisiche e Matemat. 
Napoli, 1866, pp. 125 & 126. Allied to S. clathrata (Rang), being sculptured 
with the same fine network, but the pillar-lip more produced beneath and 
bent to the right. Operculum with a raised spiral line. Gulf of Naples. 
No measurements are given. 
HETEROPODA. 
Lacaze-Dutiiiers, II. Comment les Xanthines font leur 
flotteur. Ann. Sc. Nat. iv. pp. 329-341, pi. 15 (Ann. & 
Mag. Nat. Hist. xvii. pp. 278-285). 
The author has observed that the float suspending the lanthina on the 
surface of the water is increased by complicated movements of the anterior 
part of the foot, which result in forming an air-bubble inclosed in a glu- 
tinous matter j the lanthina never swims, as many other Mollusca, by alter- 
nately dilating and .contracting the foot, nor is it able to produce a float as 
