250 THE CEPHALOPHO iA. § 221. 
of the body, numerous fasciculated plumose, or dendritic branchiae.© 
With the Cyclobranchia, and some of the Inferobranchia, the lamelli-’ 
form branchiae are situated on the furrow which separates the border of 
the mantle from the foot,” under the form of a continuous cord, or of two 
lateral rows. 
With the Scutibranchia, the two pectinal rows, which are wholly con- 
cealed in the cavity of the mantle, have, nevertheless, a certain symmetry © 
which is wholly absent with the other Gasteropoda. Thus, all the Tecti- 
branchia have only a single lamellate or pinnate branchia situated on the 
right side, rarely on the left, and which is more or less covered and some- 
times wholly concealed by a fold of the mantle.” The Pectinibranchia 
and Tubulibranchia have a pinnate or pectinate branchia, contained in 
a cavity which is situated upon the anterior portion of the back and often 
provided with a siphon on its left side.“ 
With many N udibranchia, the returning blood from the branchiae is 
emptied by several veins into the simple auricle of the heart, which (the 
heart) is situated upon the middle line of the back.” With only a 
few Gasteropoda, as also with the Cirribranchia, Cyclobranchia, and Scuti- 
branchia, the branchial veins are united into two trunks which open into 
the simple or double auricle.“ With the other Gasteropoda, which have 
an uneven, lateral branchia,® the blood passes from this last, through a 
short, simple, venous trunk, to the heart situated near its base. 
IT, Lungs. 
§ 221. 
The pulmonar yeeavity, formed in the mantle of the Pulmonata, is situated 
8 With Scyllaea, there are, on the back, two 
pairs of cutaneous lobes, between and which are 
numerous branchial vessels. With Glaucus, there 
are, upon the sides of the body, three pairs of pro- 
longations which have long, digitiform branchial 
filaments. With Thetis, the back is surrounded 
by adouble row of semi-pinnate branchiae ; while 
with T'ritonia, there is on each of its sides a single 
row of multiramose branchial tufts. With Doris, 
and Polycera, there are twenty to twenty-five 
more or less ramified branchiae, arranged circu- 
larly around the arms, and capable, from it 
cealed under a fold of the mantle (T'reviranus, 
loc. cit, p. 192, Taf. XVII. fig. 1, 2,d., or Vogt, 
loc. cit. p. 28, Taf. II. fig. 1-3, p.). 
10 With Vatvata, there is a single pinnate 
branchia which projects out of a cavity in which it 
is contained (Gruithuisen, Nov. Act. Acad. Nat. 
Cur. X. p. 441, Tab. XXXVI. fig. 2,3, 5, 12). 
The branchia is simple and pectinate with Ve erme= 
tus (Philippi, Enumer. Mollusc. Sicil. I. p. 169, 
Tab. IX. fig. 24), Rostella, and Struthiolaria. 
It is bi-pectinate with Turbo, and Janthina, and 
tri-p with Paludina. With many Pectini- 
tion, of being withdrawn into the mantle. 
7 The branchial lamellae form a complete circle 
with Patella, Chiton, and Phyllidia, and two 
lateral rows with Diphyllidia. 
8 With Fissurelia, and Emarginula, there isa 
row of branchiae on each side of the cavity of the 
mantle, while, with Haliotis, there are two rows 
on the left side. 
9 With Umbrella, Pleurobranchaea, and Pleu- 
robranchus, this br on the right 
side and half exposed, is easily seen. On the same 
side also is situated the branchial lamella often deep- 
ly concealed between the folds of the mantle, of Gas- 
teropteron, Aplysia, Bullaea, Notarchus, &c. 
But with Doridium, the branchia is on the left 
side and quite behind. 
Ancylus, which differs from the other Infero- 
branchia by its simple branchia, has, moreover, 
this peculiarity, that this organ has the form of a 
simple cutaneous enlargement on the left side, con- 
* [ § 220, note 10.] See also Leydig, loc. cit. 
for the branchiae and their intimate structure, 
with Paludina. According to this observer, they 
branchia, as, for examples, with Harpa, Cassis, 
Conus, Buccinum, Terebra, Mureax, Voluta, 
Oliva, &c., there is, beside a very large unipecti- 
nate branchia, another organ of this kind which is 
smaller and bi inate. The epithelium, which 
covers not only the branchia, but also the walls of 
the respiratory cavity, plays an important part in 
the renewal of the water in the branchial cavity, 
which takes place through its opening, or by the 
siphon of these Gasteropoda which is situated upon 
the neck usually a little to the left side.* 
ll Scyllaea, Thetis, Doris. 
12 Tritonia, Dentalium, Patella, Chiton, 
Haliotis, Fissurella and Emarginula. Among 
the Inferobranchia, Phyllidia should also be 
cited here. But with Diphyllidia, on the contrary, 
the veins appear to pass each into the auricle of the 
heart. 
13 The Tubulibranchia and Pectinibranchia, 
are unipectinate with Paludina vivipara, and not 
tri-pectinate, as above mentioned of this genus in 
general. — Ep. 
