8 
6 
CLASS XIII. 
of Zool. Soc. Iv. 1851, pp. 26, 27. [From letters of VAN DER HoEvEN, 
July and Sept. 1855, it appears that the above was no abnormity but the 
usual conformation of the males. I have had the opportunity,” he adds, 
“ of examining recently two other male specimens, and hope to have time 
to publish this year or the following, some new observations on the struc- 
ture.... The male differs from the female by the absence in the mantle of 
the lamellated glandular apparatus (OWEN’s Mem. p. 43, Pl. viu. fig. 10), 
and by a different number of the digitations. (These are less numerous in 
the female.) A chief difference, however, is the presence of the great 
conoid body at the left side (see my Contributions, p. 27, Pl. 7, figs. 10, 11). 
This singular body has at the extremity and on the outside a large disc 
perforated by the orifices of numerous crypts. As the spermatophores 
(NEEDHAM’S machines) after their passage through the penis are inclosed 
in a bag formed of two coats, of a brown colour, and of nearly half an 
inch in diameter, I believe that the glandular apparatus may secrete this 
envelop, and that consequently it is a physiological analogon of the glan- 
dular apparatus described by OWEN in the mantle of the female. The fold 
connecting the labial processes at the inferior side above the funnel is in 
the male of a different conformation, (see Contrib. pp. 26, 27). The fine 
folds of the external labial processes are totally wanting, and instead of the 
so-called olfactory organ at the commissure of the internal labial processes, 
there is the cushion-like part (with 8—11 digitations), (Contrib. P1. 8, fig. 9). 
As to the internal genital organs of the male, a large gland (testis), which 
in bulk surpasses all the other organs of the body, except the liver, is 
situated exactly where the ovary is in the female; another smaller, flat 
gland, more at the fore part, seems to secrete the spermatophora; a bag 
with an imperfect internal septum receives these spermatophore and brings 
them to the conical penis, which is situated not exactly, but nearly, as is 
the vulva (more in the mid-plane).” ] 
The genus Nautilus occurs also fossil in secondary and tertiary formations. 
Tt is the only genus still extant of a very numerous division of the Cepha- 
lopods, which lived in the seas of a former world and of which the remains 
are met with in mountain strata, especially in the older secondary forma- 
tions. Here belong the Ammonites. 
Fossil genera related to Nautilus : 
Clymenia MUENSTER. 
Comp. Mém. sur les Clyménes et les Goniatites du calcaire de transition 
du Fichtelgebirge par le Compte Dk MuENSTER, Ann. des Sc. nat., 2e Série, 1. 
1834, Zool. pp. 65—78, Pl. 1—L. Von Bucu Ueber Goniatiten und Cly- 
menien in Schlesien, Physikal. Abhandl. der Berl. Akad. der Wissench. 1838 
(section of genus Nautilus according to V. Buc). 
Lituites Breyn, Mont. 
Sp. Lituites convolvans ScHLoTH., BRonn Lethea geogn. Tab. I. fig. 3. 
Campylites Dusu., Cyrtocera GOLDFUSS. 
