470 PHILOSOPHY OF ^OOLOGY, 



(&,) Tentacula four in number. 



The branchiae are simple, tapering, or clavate, and 

 posed in transverse rows on each. These branchiae in some 

 species readily fall off, and, as if independent, are capable 

 of swimming about for a short time in the water. This is 

 executed by means of minute hairs with which their sur- 

 face is covered, and which move rapidly, pushing forward 

 the distal extremity. 



35. MONTAGUA. Branchiae in continuous rows across 

 the back. 



This genus, which differs from the other, not merely in 

 the arrangement of the branchiae, but in possessing a clus- 

 ter of short papillae on the right side, probably connected 

 with the anus, we have ventured to name in honour of the 

 late GEORGE MONTAGU, the well-known author of Testa- 

 cea Britannica, and of several valuable papers in the Lin- 

 nean Transactions, on molluscous animals. The two spe- 

 cies which may be referred to this genus, were detected in 

 Devonshire by this observer. The first, M. longicarnis, 

 (Lin. Trans, vol. ix. p. 107, tab. vii. f. 1,) is the type of 

 the genus. The other species, M. carutea, (Lin. Trans, 

 vol. vii. p. 78, tab. vii. f. 4, 5,) is probably the type of an- 

 other genus. 



36. EOLIDA. Branchiae interrupted on the back. 



This genus, which was instituted by M. CUVIER, in- 

 cludes the following British examples: I.E. papillosa; 

 2. Plumasa ; 3. Pedata ; 4. Purpurascens *. 



(2.) Branchiae disposed on lateral membranaceous ex- 

 pansions. 



These expansions serve the double purpose of support- 

 ing the branchiae, and acting as fins. 



* There is a figure of this species given in Plate IV. f. 2. 



