250 THE CEPHALOPnORA. '5' 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 Nudibranchia, 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. 



II. Lungs. 



§ 221. 



The pulmonary cavity, formed in the mantle of the Pulmonata, is situated 



6 With Scyllaea, there are, on the back, two cealed under a fold of the mantle (Treviranus, 

 pairs of cutaneous lobes, between and which are loc. cit. p. 192, Taf. XVII. fig. 1, 2, d., or Fog-t, 

 numerous branchial vessels. With Glaucus, there loc. cit. j). 28, Taf. II. fig. 1-3, p.). 



are, upon the sides of the body, three pairs of pro- 10 With Vaivata, there is a single pinnate 



longations which have long, digitiform branchial branchia which projects out of a cavity in wliioh it 



filaments. With Tlietis, the back is surrounded is contained (Gruithuiseti, Nov. Act. Acad. Nat. 



by adoul)le row of semi-pinnate branchiae ; while Cur. X. p. 441, Tab. XXXVIII. fig. 2, 3, 5, 12). 



with Tritoiiia, there is on each of its sides a single The branchia is simple and pectinate with f^erme- 



row of multiramose branchial tufts. With Doris, tiis {Philippi, Enunier. Mollusc. Sicil. I. p. 169, 



and Polycera, there are twenty to twenty-tive Tab. IX. fig. 24), RosteUa, and Strulliiolaria. 



more or less ramified branchiae, arranged circu- It is bi-pectinate with Turbo, and Janthina, and 



larly around the arms, and capable, from contrac- tri-pectinate with Paludina. With many Pectini- 



tion, of being withdrawn into the mantle. branchia, as, for examples, with Harpa, Cassis, 



7 The branchial lainullae form a complete circle Conus, Buccinum, Terebra, Murex, Foluta, 

 with Patella, Cliitun, and Phyllidia, and two O/jna, &c., there is, beside a very large unipecti- 

 lateral rows witli Diphyllidia. nate branchia, another organ of this kind which is 



8 With i'>s.9U7-e//a, and £?narg-mM/a, there isa smaller and bi-pectinate. The epithehum, which 

 row of brancliiae on each side of the cavity of the covers not only the branchia, but also the walls of 

 mantle, while, with Haliotis, there are two rows the respiratory cavity, plays an Important part in 

 on the left side. the renewal of the water in the branchial cavity, 



9 With Umbrella, Pleurobranchaea,a.nAPleu- which takes place through its opening, or by the 

 robranchus, this branchia, situated on the right siphon of these Gasteropoda which is situated upon 

 side and half exposed, is easily seen. On the same the neck usually a little to the left side.* 



side also is situated the branchial lamella often deep- 11 Scyllaea, Thetis, Doris. 



ly concealed between the folds of the mantle, of Gas- 12 Tritonia, Dentalium, Patella, Chiton, 



teropteron, Aplysia, Bullaea, Notarchus, &c. Haliotis, Fissurella and Emarf^inula. Among 



But with Doridium, the branchia is on the left the Inferobranchia, Phyllidia should also be 



side and quite behind. cited here. Kut with Diphyllidia, on the contrary, 



Ancylus, which differs from the other Infero- the veins apjiear to pass each into the auricle of the 



branchia by its simple branchia, has, moreover, heart. 



this peculiarity, that this organ has the form of a I'i The Tubulibranchia and Pectinibranchia. 



simple cutaneous enlargement on the left side, con- ♦ 



* [ § 220, note 10.] See also Leydig, loc. cit. are unipectinate with Paludina vivipara, and not 

 for the branchiae and their intimate structure, tri-pectinate, as above mentioned of this genus iu 

 with Paludina. According to this observer, they general. — Ed. 



