



the side-processes of the mantle laid 
aside, and the branchiostegal membrane 
and the shell removed ; a ccecal appen- 
dage to the pylorus as in Doris, and two 
small branchial ganglia. 
(Akera bullata has two ganglia on the left nerve, one 
on the right, Bulla only the latter, but two ad- 
ditional at the anterior extremity ). 
11, the anatomy of Chitonellus. 
12, portion of the under surface of do. 
12’, heart of Chiton marginatus. 
13, the animal of Dentalium (a foreign 
grooved species). 
a, the mantle split and turned back: 6, the foot: 
c, the mouth at the end of a proboscis: d, the 
branchiz: e, intestine: jf. anus: g, muscles. 
14, Hipponyx—parasitical upon Delphinula 
15, the remarkable genital organs of On- 
chidium, (from Amoy and apparently 
the same species as was figured by 
Cuvier) shewing that it has both testis 
and ovary distinct. The anterior cu- 
rious genital organs are not given, as 
they are accurately figured by Cuvier, 
but the extremity of his so-called “vais- 
seau mince ” is not floating but at- 
tached to the anterior extremity of the 
side groove. 
16, a portion of shell of Acmea virginea 
magnified. 
General references to the Gasteropoda. 
Jf, the foot m,themantle: 6,branchia: o, mouth 
a, anus: s, stomach: h, heart: g, salivary 
glands: 7, tongue: w, spiny languette, ov, 
ovary and oviduct: ¢ testis (mihi) which how- 
ever may be an androgynous organ, in which case 
my ovary must be a nidamentary organ: &, mu- 
cous sac or kidney : 
v, genital vesicle: c, colour 
gland or vesicle. 

PLATE 4, GASTEROPODA—THEIR REPRO- 
DUCTIVE ORGANS, te. 
Fic. 1, spermatozoa from Paludina. 
2 and 3, the same after the action of water. 
4, moving cells from the vesicle of the 
Helix, and the same after endosmosis. 




5, the reproductive organs of Helix aspersa. 
t, the testis (conjoined ovary and testis of others): 
v d, vas deferens opening into the granular 
groove: or false duct of the matrix, and so going to 
the penis, (p.): 0, theovary, (mihi,nidamentum of 
others): m, the matrix: c, the ccecal canal in 
which the ligule or spermatophore is found post 
eoitum: v, the vesicle often filled with sperma- 
ozoa and the debris of the ligule: +, the vagina 
which receives the male organ: s, the muscular 
sac containing the dart and having fimbrize which - 
probably secretes its caleareous matter as well as 
arare fluid: jp,’ the appendix of the male organ 
in which is formed the ligule. , 
6, asection of the matrix, and of the gran- 
ular false-duct (vas deferens). 
7, the penis cut off, or shewn as protru- 
ded with a portion of the enclosed ligule 
8, the dart in its muscular sac. 
9, the supposed ovary developed, shewing 
how the vas deferens opens at its lower 
part. ; 
10, spermatozoa of Helix nemoralis. 
11, the same after the action of water. 
12, the same degenerating from endosmosis 
13, the same undeveloped. 
14, spermatozoa from Lymnzus stagnalis. 
15, the same undeveloped. 
16, mother-cells of the same 
17, ootheca of Aucylus fluviatilis as deposi- 
ted on stones in rivulets. 
18, ootheca and ova of Doris aspera 
19, cotheca of Janthina yiolacea. 
20, the foot, &c., of that animal. 
21. the reproductive organs of Lymnzeus 
palustris ; 
t the testis (mihi): vd, the ciliated vas deferens going 
to the penis (p), through the receptacle (r): 0, 
the ovary : m, the matrix with its conveluted and 
ciliated part, globular gland, and laminated dila- 
ted portion: v, the vesicle. 
22, oral and lingual pieces of Dentalium. 
minty 
23, lingual pieces of Hipponyx 
24, plan of the tongue of Chiton cinereus. 
25, ditto of Chitonellus 
26, ditto of Acmea virginea. 
27, ditto of Fissurella. 






