XArTILIDJE. 
181 
Remarks. “ Nautilus Parkinsoni, Edwards, is cited by Meek as 
belonging also to Hercoglossa, Of this species only two examples 
are known to us, both from the London Clay — the one figured by 
Parkinson and also by Edwards, now in the ‘ Sowerby Collection,’ 
British Museum, the other from Colchester. Both specimens are 
remarkably large ; Parkinson’s consists merely of the casts of three 
chambers, to which a portion of the inner whorls, badly preserved, 
is attached ; the largest chamber is 8 inches in height and 6 inches 
in width. Owing to the form of the sutures some doubt originally 
existed as to whether this specimen should not be placed in Aturia. 
Although the siphuncle is cylindrical, as in Nautilus, the sutures 
suggested its being the adult of Aturia. Unfortunately the inner 
whorls are so much crushed that the form of the siphuncle in the 
young shell cannot be ascertained. The specimen from Colchester, 
which measures 11 inches in diameter, shows, however, that the 
siphuncle is cylindrical not only in the adult, but even where the 
diameter of the shell does not exceed 2^ inches. We feel justified 
therefore in concluding with Meek that Nautilus Parkinsoni belongs 
to the subgenus Hercoglossa, and not to Aturia k It may here be 
added that Conrad distinctly states in his description of Hercoglossa 
that the siphuncle is not funnel-shaped [as in Aturia], but tubular. 
He includes in He7Xoglossa the Aturia Maihewsoni of Gabb, though 
doubtfully, because Gabb did not describe the character or position 
of the siphuncle in his species, merely stating ‘ siphuncle large.’ 
“ It is open to question whether Grypoceras, Hyatt, should not 
be merged in Hercoglossa ; we are inclined to the opinion that it 
should. Thus the type species of the former {Nautilus mesodiscus, 
Hauer) is distinguished, according to Hyatt, from that of the latter 
(W. danicus, Schloth.) by the presence of a ‘ V-shaped ’ ventral lobe 
in the sutures and by a flattening of the periphery ‘ at some stage 
of growth.’ ]^ow in some species the ventral lobe, as, e. g., in the 
type, is perfectly distinct, but in others, as, for instance, N. Stram- 
hergensis, Oppel, it is so slightly indicated as to approach those 
species, such as N. Oppeli, Zittel, in which there is no such lobe. 
^ Since this was published, part of the outer shell on one side of the specimen 
has been removed and the inner whorls exposed, the siphuncle exhibiting, to 
all appearance, a cylindrical form, though the evidence on this point is not 
perfectly conclusive. The sutural characters, however, are distinctively those 
of Aturia^ and therefore N. ParJunsoni is now placed in the latter genus, 
rather than in Hercoglossa, to which it was assigned in the joint paper by 
Mr. G. C. Crick and the writer, referred to at the end of this quotation. See 
also under the genus Aturia, p. 335. 
