ADEORBIS. 541 



ADEORBIS, Searles Wood. 



Shell not nacreous, snborbicular, depressed, with few 

 volutions, deeply umbilieated below. Peritrerae entire, 

 and nearly continuous, sinuated in its inner side, and 

 slightly so externally. Operculum testaceous, multispiral. 



Animal unknown. 



We accept this genus as a good one although as yet 

 the soft parts have not been observed. There can, how- 

 ever, be little doubt that its true position is among the 

 TrocMdiE. The peculiarity of the form of the mouth 

 strikingly indicates the affinity of the somewhat dissimilar 

 shells composing it. The number of different genera to 

 which existing species have been referred indicates how 

 doubtful their position was held to be, and how necessary 

 it was to constitute them into a group apart. It has near 

 affinities with DelpMnula and Scissurella. 



These shells appear to frequent the laminarian and 

 coralline zones. They are all very small. The genus has 

 members even so far as the Chinese seas. Mr. S. V. 

 Wood enumerates five fossil species from the later British 

 tertiaries. 



A. suBCARiNATA, Montagu. 



Body whorl very large, encircled by four spiral ridges, crossed 

 by arcuated lamellar striae. 



Plate LXVIII. fig. 6, 7, 8. 



Helix svbcarinatus, Mont. Test. Brit. vol. ii. p. 438, pi. 7, f. 9. — Turt. Conch. 



Diction, p. 45. 

 Trochus rugosus. Brown, Mem. Wernei'. Soc. vol. ii. pt. 2, p. 520, pi. 24, f. 5. 

 Cingula stibcarinata, Fleming, Brit. Animals, p. 305. 



Adcorhis subcarinata, Searles Wood, Annals Nat. H. vol. ix. (1842) p. 530; 

 Crag Mollusca, p. 139, pi. xv. f. 8. 



