APPENDIX. 385 



in which they are found, were assuredly either inhabitants 

 of deep water or floaters in a great ocean like the Pacific. 



I have dedicated this most interesting creature to my 

 friend Mr. Macgillivray, its discoverer, whose researches 

 have been productive of so much new and valuable con- 

 tributions to all departments of zoological science. 



I have named the species M. pelagica. Tab. iii. fig. 8. 

 a, b, c, d. (Mus. Brit, and Geol.) 



New Genus — Cheletropis, Forbes. 



Shell spiral, turbinate, dextral, imperforate, spirally 

 ridged or double-keeled and transversely wrinkled ; spire 

 prominent, its nucleus sinistral -, aperture ovate, canalicu- 

 lated below, its outer margin furnished with two claw -like 

 lobes, the one central and formed by a prolongation of the 

 margin between the keels of the body whorl, the other 

 smaller and nearer the canal; peristome thickened, re- 

 flexed, forming a conspicuous margin. 



Operculum none ? 



Animal unknown, but certainly floating, and probably 

 pteropodous. This I infer from its habits, and from the 

 analogy of the shell with Spirialis. (Mus. Brit. & Geol.) 



The only known species, C. Huxleyi, (dedicated to Mr. 

 Huxley, Assistant Surgeon of the Rattlesnake, and now 

 eminent for the admirable anatomical researches among 

 marine invertebrata which he conducted during the voyage,) 

 is very minute, being not more than the ^4th of an inch 

 in diameter. It is translucent and of a brownish-white 

 hue. Its aspect is that of a Turho in miniature. The 

 whorls are tumid, the spire prominent ; the body whorl is 

 belted by two prominent keels, one of which is continued 

 on the whorls of the spire : between, above, and below 

 these keels are transverse membranous raised ridges, which 

 in the central division of the body whorl are curved for- 



VOL. II. 2 c 



