178 GENUS CORTICIFERA. [December. 



Gemis MAMMILLIFERA. 



A large cuticular expansion, serving as the base of 

 numerous animals, which, when contracted, assume the 

 form of mammas. 



1. M. Auricula, (Plate VIII. fig 2.) Disc greenish, 

 tentacula 26 to 30 in number, reddish; mouth small and 

 ■whitish, of a deep green colour. 



Body short, cylindric, of a reddish colour; the expan- 

 sion of the base, and of the body, is fleshy, and covered 

 "with mucus. 



These animals cover, by their large expansion, the 

 rocks at the entrance of the ports of St. Vincent and Do- 

 minica. 



2, M. Nymphcsa, Disc yellowish, a green circle at 

 the base of the tentacula^ which are placed in two rows, 

 and about fifty in number, of a light brown; mouth rosa- 

 ceous. 



Body yellowish red, short, fleshy, and contractile, as 

 in the preceding species; the mouth is divided, on each 

 side, by four or five plaits, and rises in the form of a 

 button. 



The habits of these animals are similar to those of the 

 foregoing species. Found at the island of St. Christopher. 



The animals of the genus Corticifera are distinguished 

 from the preceding, inasmuch as the former are enclosed 

 in cellules of sand, agglutinated, the cellules are likewise 

 agglutinated their whole length, and form a corticiferous 

 expansion. 



1. Corticifera ^/ard-o/flr. (Plate VIII. fig. 6, 7.) 

 Disc deep violet, whitish at the centre; tentacula twenty- 



