43 



The largest species, C. vitrea (C. gracilis, mihi), has been captured in 

 the vicinity of the Moluccas, and a small species, C. Atlantica, was taken 

 by Sir Edward Belcher at twilight, in the trawl, in the North Atlantic 

 Ocean. M. D'Orbigny describes a third species in his South American 

 Voyage, and there is the well-known species, C. fragilis, of the Mediter- 

 ranean. 



Species. 



1. Atlantica, Ad. Sf R. 3. punctata, D'Orb. 4. vitrea, Lam. 



2. fragilis, Bory. 



Figure. 



Carinaria fragilis. PI. K. Animal, showing its thick gelatinous sub- 

 stance ; head with eyes and tentacles ; proboscis and narrow gut 

 leading to the dorsal nucleus covered by the shell, from which extend 

 in feathery plumes the branchiae. Beneath the body is the natatory 

 fin. From a specimen in my possession, cast ashore after a storm at 

 Messina, and brought from thence by the Rev. L. B. Larking. 



Class 3. PTEROPODA. 



Animal ; pelagic, subgelatinous ; abdominal portion of the body 

 sometimes enclosed within a shell ; head, wliere there is a shell, 

 indistinct, toith or without tentacles ; mantle large and thin, 

 attached on either side like a winged membrane ; natatory disk 

 also wing-like ; branchiae pectinate, lodged in a cavity. 



Shell ; thin, horny or glassy, sometimes cartilaginous, variously 

 shaped, globose, triangular, cylindrical or needle-like, some- 

 times cuspidate or sharply long-spined. 



The Pteropods are a class of oceanic swimmers allied zoologically and iu 

 habit to Carinaria. They are very small, limited in kind, but abundantly 

 prolific in individuals, and obtain motion by the aid of a pair of wing-like 

 natatory fins. Only part of them are furnished with a shell, which is ex- 

 tremely thin and glassy. " In warmer seas than those which encircle our 



where are they to rest — where fix their anchor in the world of unstable water around them ? 

 They are created to live aiid are born amidst the fields of seaweed which voyagers describe with 

 amazement as covering leagues of sea within the Tropics ; and to enable them to attach them- 

 selves to the narrow leaves of the sargassum, they are furnished by their Creator with a small 

 sucker, which like a cupping-glass applied against the surface of the leaf, suspends them there 

 without exertion." — Introduction to Gonchology, p. ll'J. 



