Jouannetia Darwinii, H. and A. Adams, ii. p. 330. Fischer, Jo-urn. Conch, 

 2d ser. iii. p. 51. Chenu, Manuel, ii. f. 39, 40. 



Pholas cornea ? Sowerby, Zool. Proc. 1834, p. 72. Catlow, Conch. Nomenc. 

 p. 3. Hanley, Desc. Cat. p. 9. 



Hab. — California, (penita.) W. Columbia, (cornea.) Chiloe (Darwinii.) 



Coll. Acad. Nat. Sciences. 



P. Darwinii, Sowb. is the young of this species ; I have also included 

 Sowerby's P. cornea, as his description seems in the main to correspond, I 

 cannot understand why several of Sowerby's and D'Orbigny's species were 

 omitted from Sowerby's Monograph and are not contained in Gray. Nor is 

 any reference made to them. 



Genus Jouannetia, Desmoulins. 

 Jouannetia, Chas. Desmoulins, Bull. Linn. Soc. Bordeaux, ii. p. 244. Gray, 



Ann. and Mag. Nat. Hist. 2d ser. viii. p. 382. H. and A. Adams, 



Genera, ii. p. 330. Chenu, Man. ii. f. 36. Fischer, Journ. Conch. 



2d ser. iii. p. 51. 

 Triomphalia, Sowerby, Monog. Thes. Conch, ii. p. 500, 1849. Sowerby, Zool. 



Proc. 1849. 

 Pholas, (part.) Deshayes, in Lam. An. sans Vert. vi. p. 46. 



* Valves with two impressed radiating grooves. 

 J. Cumin gii, Sowerby. (Sp.) 

 Triomphalia Cumingii, Sowerby, Zool. Proc. p. 161, 1849. Sowerby, 



Monog. Triomphalia, Thes. Conch, ii. p. 502, t. 106, f. 56, 57. 

 Jouannetia Cumingii, Gray, Ann. and Mag. Nat. Hist. 2d ser. viii. p. 382. 

 H. and A. Adams, Genera, ii. p. 330. Chenu, Man. Conch, ii. f. 38. 

 Fischer, Journ. Conch. 2d ser. iii. p. 51. 

 Hab. — Philippines. 



This beautiful little species merits the name of the following instead of that 

 which it bears, being almost entirely spherical. 



J. globosa, Quoy. (Sp.) 



Pholas globulosa, Quoy, "Voy. Astrolabe, Mollusques, p. 549, t. 85, f. 16 — 18. 

 Triomphalia globosa, Sowerby, Proc. Zool. Soc. p. 160, 1849. Sowerby, 



Monog. Triomph. Thes. Couch, ii. p. 501, t. 106, f. 54, 55. 

 Jouannetia globosa, Gray, Ann. and Mag. Nat. Hist. 2d ser. viii. p. 382. 

 H. and A. Adams, Genera, iii. t. 90, f. 3, 3a b. Chenu, Man. ii. f. 36. 

 Fischer, Journ. Conch. 2d ser. iiii. p. 51. 



Jouannetia globulosa, Gray, Figs. Moll. Auim. t. 338, f. 3. 



Hab.— Philippines. 



Coll. Acad. Nat. Sci. Coll. G. W. Tryon, Jr. 



This shell is not so round as J. Cumingii, being somewhat ovate in form. 

 It is also a smaller species, and differs in the posterior margin of the right 

 valve being toothed. In the latter respect it resembles J. pectinata, but 

 the teeth are larger and not so numerous, and the surface of the valves is 

 bisulcate. 



** Valves with a subcentral impressed radiating groove. 

 Subgenus Pholadopsis, Conrad. 

 Genus Pholadopsis, Conrad, Proc Acad. Nat. Sci. p. 156, 1849. 



As Conrad's type species differs from the others in having but one radiating 

 groove, Dr. Gray has very properly separated it as a subgenus. 



J. pectinata, Conrad. (Sp.) 



Pholadopsis pectinata, Conrad, Journ. Acad. Nat. Sci. 2d ser. i. p. 279, t. 

 39, f. 3. 



