ACEPHALA NUDA. 113 



Of the Salp^, properly so called, some have a gelatinous dark co- 

 loured jjlate, in the substance of the mantle and above the visceral 

 mass, which may be the vestige of a shell*. 



In otlicrs it is a simple prominence, of the same nature as the rest 

 of tlie mantle, but thicker f . 



Others again have neither plate nor prominence, but their mantle 

 is extended by points, and of these 



Some have a point at each extremity J. 



Others have two at the extremity nearest the mouth §, and even 

 three or more ||. 



Some have but a single one at this same extremity^. 



The greater number is simply oval or cylindrical**. In the 



AsciDiA, Lin. — Theyton of the Ancients, 



The mantle and its cartilaginous envelope, which is frequently very 

 thick, resemble sacs everywhere closed, except at two orifices, which 

 correspond to the two tubes, of several bivalves, one serving to admit 

 water and the other affording a passage to the faeces. The branchiae 

 form a large sac, at the bottom of which are the mouth and the vis- 

 ceral mass. The envelope is much larger than the mouth, which is 

 fibrous and vascular, and on which, between the two tubes, is one of 

 the ganglions. These animals attach themselves to rocks and other 

 bodies, and are deprived of all power of locomotion ; the chief sign 

 of vitality which they exhibit, consists in the absorption and evacu- 

 ation of water through one of their orifices ; when alarmed they eject 

 it to a considerable distance. They abound in every sea, and some of 

 them are eaten ff . 



* Salpa srutigera, Cuv. Ann. du Mus., IV, Ixviii, 4, 5, probably the same as the 

 Salpa gibha, Bosc, Vers, II, xx, v. 



t Salpa Tilesii, Cuv., loc. cit. 3 ; — S. punctata, Forsk., xxv, C. ; — S. pelagica, 

 Bosc., loc. cit., 4; — S. infundibuUformis, Q,uoy and Gaym., Voy. de Freycin., 

 Zool. 74, f. 13. 



X Salpa maxima, FoTsk., xsxv, X ', — S.fusi/ormis, Cuv., loc. cit., 10, perhaps 

 the same as Forsk., xxxvi ; — S. mucronata, lb., D ; — 5'. uspera, Chamisso, f. iv ; — 

 S. runcinata. Id., f. v, G, H, I. But, according to the author, it is the aggregate 

 generation of a species, of wliich the other generatian is cylindrical. 



§ Salpa democratica, Forsk., xxxvi; — S. longicaudu, Qnoy and Gayra., loc. cit., 

 pi. 73, f. 8 ; — S. constata, lb., f. 2. 



11 Salpa triaispis. lb., f. & ; — S. spinosa, Oito^tiow Ac. Nat. Cur., t. pi. xlii, 

 f. 1. 



*\ Holothuria zonaria, Gm., Pall., Spic, X, i, 17; — Ttialia Ungiiluta, Blumcnb., 

 Abb., 30. 



** Salpa ocfofora, Cuv., loc, cit., 7 ; perhaps the same as the small Dagysa, 

 Home, loc. cit., Ixxiii, 1 : — S. africana, Forsk., xxxvi, C ; — S.fasciata, lb., U; — 

 S. confcderata, lb., A ; perhaps the same as the S. gibha, Bosc, loc. cit., 1, 2, 3 ; — 

 S. polycratica, lb., F; — S. cyliadnca, Cuv., loc. cit., 8 and 9; — Dagysa strumosa. 

 Home, I, c, Ixxi, I ; — S. ferruginea, Chamiss., X: — S. ceerulescens, Id., ix ; — S. va- 

 ginata. Id., vii, and several others. 



ft The whole genus Ascidia, Gm., to which must be added the Asc. gelaliiwsa, 



Zool. Dan. xliii ; — Asc. pyriformis, lb., clvi ; — Salpa sipho, Forsk., xliii, C ; — Ascidia 



microsma, Redi, Opusc, III, PI., App., VII, the same as the Asc. sulcata, Coque- 



bert. Bullet, des Sc. Avril, 1797, I, 1; — Asc. glandifurmis, Coqueb., lb. — N.B. 



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