THE CUTTLE-FISH. 
119 
8. In development the embryo does not present a longitu- 
dinal median groove. 
9. The body is soft, is protected by a calcareous shell, and 
not by a hard chitinoiis envelope. 
10. It does not consist of a longitudinal series of similar 
segments, either internally or externally. 
11. The heart is auriculo-ventricular in structure. 
12. In the embryo the haemal not the neural surface is first 
developed. 
The cuttle-fish differs from man by those of the above 
characters which are numbered 1, 2, 3, 4, 5, 6, 10, and 12. 
It differs from the lobster, on the other hand, by those of 
the above characters which are numbered 1, 7, 9, 10, 11, 
and 12. 
The cuttle-fish, moreover, agrees with the other ceplialo- 
pods, and with all snails, slugs, whelks, limpets, periwinkles, 
and pteropods, not only in the above twelve characters, but also 
in the presence of a head and of an odontophore ; in the gills 
not being in the form of lamellar plates ; and in the shell, what- 
ever its form, being single, and not divided into two valves, one 
on the right and the other on the left side of the animal, as is 
the case in all oysters, mussels, cockles, and other similar 
creatures. 
No animal known to exist now, or ever to have existed in 
past time, presents us with any intermediate condition tending 
to bridge over the chasm which yawns between the cuttle-fish 
type and the lobster type on the one hand, or between the 
cuttle-fish type and the human type on the other. 
Other types, however, exist, which are perhaps as distinct 
from any of these as they are from each other. Hereafter one 
of the other types here alluded to may form the subject of yet 
another zoological sketch. 
EXPLANATION OF PLATE.* 
Fig. 1, Sepia. Ventral aspect. 
t tentacle. m moutli. 
t' ditto, partly retracted. I lateral fin. 
f funnel. 
* These figures have been drawn (hy the kind permission of the Museum 
Committee of the Poyal College of Surgeons) from some specimens which 
form part of the educational series lately added so advantageously to the 
College of Surgeons’ Museum hy its zealous Curator, Mr. W. H. Flower, 
F.R.S. 
