PKOTEEDIXGH OF UNITED STATES NATIONAL MUSEUM. 311 



grciit CryptocJilton Stellcri of iiiodorii author.^. Some Kspecimeus of Stel- 

 leri m the Berliu ^luseuiu are marked amlciilatna on very ancient labels, 

 so there can be little doubt tliat the two species were contbunded by the 

 earlier authors. 



Genus CRYPTOCUITON Midd. and Gray. 



Midd. Mill. Ross, i, pp. 1-9G, pi. 1-9, 1847. Type C. steUeii Midd.— Gray, P. Z. S. 

 1847, pp. 05, 09, U\9; Guide, p. 185, 18.57. 



Valvaj omnino in zona immersae; laminse iusertionis rude mopa- 

 loideae; lam. sutur. tarn postice quam antice junctai, postice trisinuatte; 

 zona minutissime fii^ciculatim i)ilosa ; branchiae ambientes. 



This genus was simultaneously described under the same name by 

 Gray and Middendorf, apparently without knowledge of each other's 

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

 ously suijposed his type to be the C. amicnlatvs of Pallas, and called it 

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

 really referred to C. Stelleri. 



It appears i^robable, from some of Pallas' specimens examined by me 

 in the Berhn Museum, that he included this species with the amiculatus 

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

 one might do the same. 



Cryptochiton Stelleri. 



Chiton Stelleri Midd. Bull. Acad. Sci. St. P^tersb. vi, p. UG, 1846. 



Chiton (Ci-yptochiton) Stelleri Midd. Mai. Ross, i, p. 93, t. i-ix, 1847; M^m. 



de FAcad. Imp. Sci. St. P6tersb. 6me s6r, vi, p. 101, 157, 1849. — Sclirenck, 



Amur-Land Moll. p. 271, 1867. 

 Chiton amiculatus Sowerby (not Pallas), Concb. 111. f. 80, 80 bis, 1839. — Gray, 



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

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



sitkensis Midd.) 

 Chiton chlamys Reeve, 1. c. j)l. xi, f. 60, 1847 (from type, Cpr.). 

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



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



1863, p. 648. 

 {PatellcB longw Bondeletli aiif Kuriliscli K^ru, Stcllor, Beschreib. Kamtscb. 



p. 177, 1774.) 



0. t. intus ; v. i^ost. mopaloidea, muerone obtuso ad posticam trien- 

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

 spicuisj lam. sut. anticis latioribus, junctis, sinu jugali alto, modico, 

 subplauato ; v. ant. muerone ad (piartam partem posticam, normaliter 

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

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

 sinu postico altissimo, pyramidali, frustrato ; v. centr. mucr. ad (piintam 

 partem posticam; haud seu interdum 1-fiss. 5 lam. lat. et sutur. ant. 

 hand separatis, sinu jugali angustiore, altissimo, irregulariter arcuate, 



