SYSTEMATIC 

 ARRANGEMENT OF TUNICATES. 





CLASS XL 

 TUNICATA. 



ANIMALS without distinct head, inclosed in an external covering 

 coriaceous or membranous, and furnished with two apertures. A 

 second tunic included in the fornier, perforated by two orifices cor- 

 responding to the apertures of the external covering. Cibarious 

 canal with mouth and anus internal, concealed. Respiration bran- 

 chial, branchiae situated internally in front of the internal mouth or 

 the commencement of the oesophagus, of different form in different 

 cases, never divided into four laminae. Heart tubular, propelling 

 the blood in a mutable direction. 



ORDER I. Thaliacea. 



Body prismatico-cylindrical, with two apertures opposite, sub- 

 terminal. Covering pellucid, thin, rigid. Animals swimming 

 freely, drawing in the water by one aperture, expelling it by 

 the other. 



Family I. Salpina. (Characters of the order those also of the 

 single family.) 



Salpa FORSK., GMEL., Cuv., LAM., species of Holothuria L. 

 ( Thalia BROWN, BLUMENBACH, Dagysa BANKS and SOLAND., GMEL., 

 HOME). Branchiae extended obliquely through the internal cavity 

 of body. Form in each species two-fold, the solitary progeny alter- 

 nating with the associated. 



Comp. P. FOKSKAL Descriptions animalium, Hauniae, 1775, pp. 112 

 117; ejusd. Icon. Rer. natur. ibid. 1776, Tab. 35, 36; Cuv. Mem. (v. supra 

 p. 691); A. DE CHAMISSO De Animalibus quibusdam e Classe vermium. 

 Fasciculus i. De Salpa. Berolini, 1819, 4to; MEYKN 1. 1.; ESOHRICHT 

 1. 1. ; KROHN Observations sur la generation et le developpement des Biphores, 



