ADEORBIS. 231 



in his ' Elements of Conchology : ' " disk small, oval, 

 elevated on a short pedicle, and furnished at its hinder 

 extremity with a small horny operculum ; head flattened, 

 and prolonged into two tentacles, at the base of each of 

 which is a short pedicle, supporting the eyes ; the mantle 

 is reflected into a collar around the aperture." And he 

 remarks that it differs from Turbo and Trochus in the 

 head not being snout-shaped, " but prolonged, some- 

 what after the manner of Bucdnum and Purpura, into 

 two elongated tentacles." The family is called Archi- 

 tectoniddds by Messrs. Adams, and Architectomidce by 

 Dr. Gray ; the former place it near Eulimidae. Searles 

 Wood was anticipated in giving a name to the present 

 genus. In an ' ' Enumeration of Marine Shells " found 

 on the South Devon coast, published in 1829 (a copy 

 of which was presented to me by Dr. Turton "from 

 the author"), the genus Tornus, signifying a turner's 

 wheel or lathe, was characterized as follows : " Shell 

 orbicular, depressed, aperture oval or roundish; pillar 

 none. Operculum horny. Includes Helix subcarinata" 

 This publication was anonymous, a circumstance which 

 may deprive the author of the right of precedence 

 according to the laws of scientific nomenclature. I 

 therefore retain Adeorbis, although the other name is 

 preferable. Perhaps this genus should merge in Sola- 

 rium. Many species assigned to it by Mr. S. Wood and 

 others must be removed from it, and placed in different 

 genera. 



( ~ V-A- ) 



ADEORBIS suBCARiNA'Tus*,lMontagu; r' 



Helix subcarinata, Mont. Test. Br. p. 438, t. 7. f. 9. A. subcarinata, F. 

 & H. ii. p. 541, pi. Ixviii. f. 6-8. 



SHELL nearly circular, solid, semitransparent when fresh, 



* Somewhat keeled. 



