246 PATELLID^E. 



it is short and free, except at the base. Loven, who is 

 certainly not inferior to any one in his knowledge of 

 the organization of the Mollusca, reunites all in the old 

 genus Patella. Certain species are eyeless ; but the 

 genera Eulima, Mangelia, Cylichna, and Amphisphyra 

 offer analogous cases of such a deficiency of the so- 

 called visual organs. 



The name Tectura has the precedence of Acmcea 

 (Eschscholtz) by three years. It was originally Tecture ; 

 and although the termination is not Latin, I am inclined 

 to adopt it as now spelt, in justice to Audouin and 

 Milne-Edwards, the distinguished French zoologists, 

 who first indicated the genus, as well as to Cuvier, who 

 afterwards named it and defined the characters in his 

 report to the Academy of Sciences in 1830 on their 

 account of the Invertebrata of the French coasts. The 

 name A cmcea, besides, is objectionable, being derived from 

 an adjective. Quoy and Gaimard called this genus 

 Patelloidea, and Gray Lottia. Forbes proposed to form 

 another genus, with the name of Iothia (afterwards 

 changed by him and Hanley to Pilidium), for one of 

 the species. The Tectura? inhabit both the Atlantic and 

 Pacific Oceans ; and some have been found in the newer 

 tertiary strata. Their bathymetrical range is extensive. 

 The littoral species have eyes, while those living in deep 

 water have none. 



1. Tectura tes'tudina'lis *, Miiller. 



Patella testudinalis, Mull. Prodr. Zool. Dan. p. 237. AcnicBa testudinalis, 

 F. & H. ii. p. 434, pi. lxii. f. 8, 9, and (animal) pi. A A. f. 2. 



Body white : mantle covered with vibratile cilia ; margin 

 fringed with minute white cirri : head large, somewhat rounded 

 and convex : tentacles awl-shaped, long, and slender : eyes 

 small : gills whitish, lanceolate, and ciliated : foot oval and 

 very broad, with plain and nearly level sides. 



* Like tortoiseshell. 



