46 MOLLUSCA. 



and homy shell. The anus opens behind the branchiae, and is 

 frequently concealed under the lateral crests ; the vulva is before on 

 the right, and the penis projects from under the right tentaculura, 

 The seminal fluid is conducted in coitu, from the penis to the vulva 

 by a groove, which extends from one to the other. An enormous 

 membranous crop leads to a muscular gizzard, armed internally with 

 cartilaginous and pyramidal corpuscles, which is followed by a third 

 stomach sown with sharp hooks, and by a fourth in the form of 

 a caecum. The intestine is voluminous, and the animal feeds on 

 fucus. A limpid humour, secreted by a peculiar gland, and which 

 in certain species is said to be extremely acrid, is exuded through an 

 orifice near the vulva, and from the edges of the mantle oozes an 

 abundant liquid of a deep purple colour, with which, when in danger, 

 the animal tinges the water for a considerable extent. The ova are 

 deposited in a kind of long, interlaced, glairy net work, of extreme 

 tenuity. In the seas of Europe we have : 



Apl. fasciata, Poiret ; Rang. Apl., pi. vi, vii. Black; margined 

 with lateral red crests : one of the large species. 



Apl. punctata, Cuv.; Ann. du Mus., tome II, p. 287, pi. 1, f. 

 2 4 ; Rang, Apl., pi. xviii, f. 2. Lilac, sprinkled with greenish 

 points. 



ApL depitans,L.', Bohatsch., Anim.Mar. pi. i andii; Rang., 

 pi. xvi. Blackish, with large greyish, clouded spots. 



Several other species are found in distant seas*. 



DOLABELLA, 



The Dolabettae only differ from the Aplysiee in the position of the 

 branchiae and their surrounding envelope ; they are at the posterior 

 extremity of the body, which resembles a truncated cone. Their 

 lateral crest presses closely on their branchial apparatus, merely 

 leaving a narrow furrow ; their cell is calcareous. They are found 

 in the Mediterranean and in the Indian Ocean.f 



NOTARCHUS, CUV. 



H ave their lateral crests united and covering the back, a longitu- 



* Aplysia brasiliana, Rang, pi. viii, 1, 2, 3 ; A. dactylomela, Id., IX; A. pro- 

 tea, Id., X, 1 ; A. sorex, Id., X. 4, 5, 6 ; A. tigrina, Id., XI ; A. maculata, Id. 

 XII, 1 5; A. marmorata, Blainv. Journ. de Phys., Janv., 1823, Rang, XII, 6, 7 ; 

 A. Keraudrenii, Id., XIII ; A. Lessonii, Id., XIV; A. camelus, Cuv., Ann. du 

 Mus., and Rang, XV, 1 ; A. alba, Cuv., Ib., and Rang, XV, 2, 3 ; A. napolitana, 

 Id., XV, bis; A. rirescens, Risso, Hist. Nat. Mer., pi. 1,7. It is well, however, 

 to observe, that most of the Aplysise having been drawn from specimens preserved in 

 spirits, the truth of the specific characters of some of them may be doubted. 



f* Dolabella Rumphii, Cuv., Ann. du Mus., V, xxix, 1 : and Rumph. Thes. 

 Amb., pi. x. 6, from the Molluccas, or Aplysia Rumphii, Rang, pi. i ; ApL ecaudata 

 Rang, pi. ii ; A. truncata, Id. ; A. teremidi, Id. Ill, 1 ; A. yigas, Id., 111,4 ; 

 A.Hassdtii, Id., XXIV, 1. 



J Notarchus gelatinosus, Cuv., to which M. Rang associates the Eursutella Savig- 

 niana, Descr. de 1'Eg., ZooL, Caster., pi. ii, f. 1,2, and Rang, ApL, pi. xx, and his 

 ApL Pleii, pi. xxi, and some small species. 



