310 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



It is even rarer than the last species, and hardly known in collections. 



The gills are median; mantle-edge broad and even; the veil is pecti- 

 nated and the anterior edge of the muzzle has a sort of rim or margin, 

 besides. 



Subgenus Chlamtdochiton Dall. 



Amicula Cpr. pars; nou Gray, Adams, etc. 

 Chlamydochiton Dall, Proc. Nat. Mus. p. 1, Jan. 1878. 



Cblamydochiton amiculatus. 



Chlamydochiton amiculatus Dall, 1. c. 



Chiton amiculatus Pallas, Nova Acta Petrop. ii, p. 241, pi. vii, f. 2G-30, 1788. — 



GmeliD, Syst. Nat. p. 320G, 1790.— Wood, Geu. Couch, p. 13, 1815.— Dill- 



wyu. Cat. Rec. Shells, i, i>. 6, 1817. — Blainville, Diet. Sci. Nat. xxxvi, p. 



546, 1825.— Mid<l. Mai. Eoss. i, p. 96, 1847.— H. & A. Adams, Gen. Eoc. 



Moll, i, p. 480, 1854. 

 Not C. amiculatus Sowerby, Conch. 111. f. 80, 1839, nor of Gray, P. Z. S. 1847, 



pp. 65, 69, 169, = C. Siellcri Midd. 

 Not C. amiculatus Wood, Ind. Test. f. 12, 1828, = C. vestitus (probably).—? Eeeve, 



Conch. Icon. Chiton, f. 59, 1847. 



C t. extus Cr. Stelleri, jun. simili, sed apicibus valvarum rotundati.s 

 extantibus ; intus, laminis v. post, mopaloideis, utr. hit. (et v. centr.) 

 unilissatis ; sinu caudali lato, altiore ; lam. sut. anticis modicis junctis, 

 sinu lato ; postic's majoribus, regulariter arcuatis, extus hand sinuatis, 

 postice sinu hito, alto, subapicem phiuato, haud laminato ; fissuris usque 

 ad apices sulcatis ; zona coriacea, Iteviore poris seriebus 2 circa suturas 

 et marginem, majoribus; seriebus inter valvas et iriegulariter supr.i 

 zonam sj)arsis, minoribus; setis porarum panels, longioribus, haud 

 spiculosis. Lon. 75, Lat. 40 ram, (Q)r.) 



Hah. — " Japan," London dealer; Kuril Islands, Pallas and Steller; 

 Farallones Islands, California, Newcomb ! Two specimens examined. 



This species x)robably has about the same distribution as C. Stelleri, 

 tliough much rarer, and may by collectors have been taken for an im- 

 perfect or immature specimen of that moUusk ; when dry, to a casual 

 glance they api)ear very similar, the minute apices of the valves being 

 hardly visible. The coating of the girdle is, however, of a wholly 

 diHereut character. Dr. Carpenter would have reserved the name 

 Amicida Gray for this species, but that name cannot legitimately be 

 separated from its typical species {vesUta), which belongs in the other 

 subgenus. The ambient gills are the only sound character. The pores, 

 which gave Dr. Carpenter a great deal of unnecessary trouble, are in 

 this group not even of specific importance. I have only seen specimens 

 in Dr. Carpenter's hands, and insert his description of the characters. 

 It is doubtless one of the very rarest of the Chitons. Its nearest allies 

 are A. Pallasii and vestifa. 



The figures given by Pallas are sufficient to identify the species very 

 weU, but in his remarks he quotes notes by Steller, which refer to the 



