MOLLUSCA. 781 



QUATREF. principally differs by the absence of the lateral prolongations of 

 the foot, which CUVIEB regarded as a third pair of tentacles in jEolidia. 

 See QUATREF AGES Ann. des Sc. nat., 2e Se'rie, Tom. xix. Zoologie, pp. 

 271 312, PL ii ; comp. ALDER and HANCOCK Annals of Nat. Hist. xiv. 

 1844, pp. 125129. 



Tergipes Cuv. (Amphorina QUATREF., and Psilocerus MENKE). 

 Branchiae clavate or obovate, not numerous, placed in a double row. 

 Tentacles four or two. 



Sp. Tergipes lacinulatus, Limax Tergipes FORSK., Icon. rer. natur. Tab. xvi. 

 fig. E ; Tergipes psilocerus nob. L. BOMME, Verhandel. van het Zeeuwsch 

 Genootsh. in. 1773, pp. 296298, PI. (p. 318) fig. 3 ; on the sea-wiers of 

 the island of Walcheren. (This little animal certainly does not differ 

 notably from Amphorina Alberti QUATR. Ann. des Sc. not., 30 Se'rie, I. 

 PL in. fig. 5, which, however, is smaller.) 



Comp. on Tergipes A. V. NORDMANN Versuch einer Monographic von 

 Tergipes Edwardsii, Mem. de I'Acad. de St. Petersbourg, savants etrangers, 

 Tom. IV. 1845, (given in part in Ann. des Sc. not., 30 Se'rie, v. 1846, 

 pp. 109 1 60, PL i.) The generic name of Tergipes rests on an observa- 

 tion that the animal creeps on its back by means of the branchiae, which is 

 very doubtful. 



Calliopcea D'OKBIGNY. 



Comp. D'ORBIGNY, GUERIN Magas. de Zool. 1817, Moll. PL 108 ; ALDER 

 and HANCOCK Ann. of Nat. Hist. xn. p. 233, MILNE EDWARDS Ann. des 

 Sc. nat. 2e Se'rie, xvni. 1843, p. 33, PL X. fig. 2. 



Hermcea LOVEN. 



Comp. Ofversigt af Kongl. Vetensk. ATcad. ForliandL 1844, p. 50. 



Cavolina BRUG. 



C. Branchiae dorsal, cloven, penicillate or arborescent. 



Flabellina Cuv. 



Glaucus FORSTER. Body elongate, posteriorly subulate or fili- 

 form. Four short tentacles. Branchiae digitate or palmate, lateral, 

 three on each side. 



Sp. Glaucus hexapterygius Cuv. Ann. du Mm. vi. PL 61, fig. IT, pp. 427 

 430 (Mem. sur les Moll. No. 6), R. Ani., id. ill., PL 29, fig. 3 ; although 

 the figure in BLUMENBACH Abh. naturh. Gegenst. No. 48, has eight and not 

 six branchiae, QUOY and GAIMARD are of opinion that this species denoted as 

 Glaucus atlanticus cannot be separated from the preceding, and that only a 

 single species of it is known ; comp. Voyage de V Astrolabe, n. pp. 279 283 ; 

 also G. BENNETT always saw only six branchiae ; he observed that the animal 

 attacked and swallowed Porpita that were placed in a glass with it. The 



