PEOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 311 



great Cryptocliiton Stelleri of modern authors. Some specimens of Stcl- 

 leri in the Berhn JMuseum are marked amieulatus on very ancient hxbels, 

 so there can be little doubt that the two species were confounded by the 

 earlier authors. 



Genus CRYPTOCHITON Midd. and Gray. 



Midd. Mai. Ross, i, pp. 1-96, pi. 1-9, 1847. Type C. stelleri Midd.— Gray, P. Z. S. 

 18-17, pp. 65, 69, 169 ; Guide, p. 185, 1857, 



Valvae omnino in zona immersse; laminsB insertionis rude mopa- 

 loideee; lam. sutur. tam postice quam antice junctte, postice trisinuat^j 

 zona minutissime fasciculatim pilosa j branchiae ambientes. 



This genus was simultaneously described under the same name by 

 (xray and Middendorf, apparently without knowledge of each other's 

 labors, and both having the same species in view, though Gray errone- 

 ously supposed his type to be the C. amieulatus of Pallas, and called it. 

 by that name ; his diagnosis and synonymy, however, showing that ho 

 really referred to C. Stelleri. 



It appears probable, from some of Pallas' specimens examined by me 

 in the Berlin Museum, that he included this species with the amiculatiis 

 in his distribution, and, in fact, unless carefully examined, almost any 

 one might do the same. 



Cryptochiton Stelleri. 



Cliiton Stelleri Midd. Bull. Acad. Sci. St. Pdtersb. vi, p. 116, 1846. 



Chiton (Cryptochiton) Stelleri Midd. Mai. Eoss. 1, p. 93, t. i-ix, 1847; Mem. 



de I'Acad. Imp. Sci. St. Petersb. 6me s6r. vi, p. 101, 157, 1849. — Sckreuck, 



Amur-Land Moll. p. 271, 1887. 

 Chiton amieulatus Sowerby (uot Pallas), Couch. 111. f. 80, 80 bis, 1839. — Gray, 



P. Z. S. 1847, pp. 65, 69, 169. 

 Chiton sitlcensis Reeve, Conch. Icon. Chiton, pi. x, f. 55, 55 b, 1847. (Not C. 



sitlcensis Midd.) 

 Chiton ehlamys Reeve, 1. c. pi. xi, f. 60, 1847 (from type, Cpr.). 

 Cryptochiton Stelleri Gray, Guide, p. 185, 1857. — H. & A. Adams, Gen. Rec. 



Moll, i, p. 479, iii, pi. iv, f. 1, 1 a, 1854. — Carpenter, Sujjpl. Rep. Brit. As. 



1863, p. 648. 

 {Patella; longw Eondeletli auf Kurilisch K6ru, Steller, Beschreib. Kamtsch. 



p. 177, 1774.) 



C. t. intus ; v. post, mopaloidea, mucrone obtuso ad posticam trien- 

 tem ; sinu caudali alto, lato ; fissuris utr. lat. una, subposticis, con- 

 spicuis; lam. sut. anticis latioribus, junctis, sinu jugali alto, modico, 

 subplanato ; v. ant. mucrone ad quartam partem i)osticam, norm alitor 

 utr. lat. 1- et ant. 3- (id est omnino 5-, sed interdum 4-0-, sen 7) fissata ; 

 lam. sut. posticis longis, lateraliter conspicue sinuatis, medio junctis, 

 sinu postico altissimo, i^yramidali, frustrato ; v. ceutr. mucr. ad (luintam 

 partem posticam ; hand sen interdum 1-fiss. ; lam. lat. et sutur. ant. 

 hand separatis, sinu jugali angustiore, altissimo, iiTegulariter arcuato, 



