ZOOLOGY. 581 



Order 1 . Protozooid Kracken Rumpfkracken. 



3499. Body sacciform, mostly gelatinous, without 

 head and eyes ; species androgynous. They are destitute 

 of independent locomotion, most of them being quite 

 stationary or fixed, and surrounded frequently by a shell ; 

 some few float about passively in the sea. 



Fam. 1. Infusorial Kracken Salpa. 



The Salpce are gelatinous, freely natant cylinders, 

 perforated by an open tube, within which are situated 

 the branchiae, heart, mouth, intestine, and liver, without 

 any tentacula. They continue to hang for a long time 

 to each other, as though they were in the ovary. 



They undergo a remarkable metamorphosis, which 

 traverses two generations, the young meanwhile not 

 resembling the mother but the grandmother. 



Body within a sacciform mantle, with two opposite 

 respiratory apertures. 



Fam. 2. Polypary Kracken Ascidia. 



The Ascidice have a sacciform, body with two co-ap- 

 proximate respiratory apertures ; branchiae internal and 

 trellis-shaped. 



These gelatinous or cartilaginous animals adhere 

 firmly to rocks, with the respiratory apertures directed 

 upwards as in the Mussels, but the branchiae are not 

 foliiform ; the internal cavity is lined with a membranous 

 sac, upon which the branchial vessels are dispersed in a 

 trellis-like manner. At the bottom of and within the sac 

 is the mouth, which is destitute of tentacula. Intestine, 

 liver, and a heart that is simple or undivided. Mode of 

 propagation unknown. 



They are frequently connato-sessile, like the Polyps. 



Fam. 3. Acalephan Kracken Cirripedia. 



Body sacciform, without branchial openings, oral aper- 

 tures situated at the inferior extremity of the longitudi- 

 nal fissure in the mantle, and provided with a kind of 

 maxillary apparatus ; above or behind the mouth are 

 annulate or horny filaments representing caudal fins or 

 feet, upon the basal joints of which is a branchial fila- 



