312 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



hand planato ; lam. post, super-sutiiralibus minoribiis, longis, a sinibus 

 marginalibus couspicue separatis ; shiu postico altissimo, irregulariter 

 gothico, lam. junctis ; valvis omnibus mncronatis, mucrone sen umbili- 

 coideo seu puuctato sen pustuloso ; zona omuino fasciculis minutis 

 spicularum minimarum irregulariter conferte instructfi. {Cpr.) Lon. 

 200, Lat. 75 mm. Div. 130o. 



Uab. — Japan Sea ; Sakalin Id. ; Kuril Ids. ; Kamchatka (southern 

 extreme) ; the Aleutian Islands and the \^'hole coast southward to 

 Monterey and the Santa Barbara Islands, California. Usually found 

 just below tide-marks, and often cast up on the beach in great numbers 

 by severe gales. Collected abundantly at Unalashka and Sitka, also at 

 Monterey, Dall! 



This the largest and in many other respects the most remarkable of 

 all Chitons is readOy recognized by its wholly covered valves, no indi- 

 cation of which is evident, even under the skin, in fresh examples. It is 

 covered with cells, each holding a fascicle of small spines, which, when 

 dry, have an urticating effect upon the skin of those who may handle 

 them. The foot and softer parts are used as food by the Aleuts and 

 Indians; they are eaten in the raw state. The back is of a fine ferru- 

 ginous red when fresh ; dried specimens arc usually more or less dis- 

 torted and mauled ; one of those figured by Eeeve appears to have been 

 partly rotten. 



There is a good deal of variation in the size and relative proportions 

 of the valves in dilierent individuals, and the fissures are sometimes 

 partly abortive or abnormally multiplied. 



The soft parts of this species have formed the subject of an extensive 

 monograph by Dr. Middendorf in his first part of the Beitr. Mai. Eos- 

 sica. To that work the student is referred for details. 



Genus KATHEEINA Gray. 



Eatlwrina Grtiy, P. Z. S. 1847, p. 65. Type E. iumcata Wood. 



Lorica parva; zona lasvis, in suturas valde expanssi; laminae valde 

 antice projectoe, v. post, saepe lobatie; sinus altissimus, spongiosus; 

 brauchiiie ambientes. 



This is an aberrant genus. In the smaUness of the exposed portion 

 and smoothness of the girdle it resembles Fhacellopleura ; in the extreme 

 anterior projection of the plates, and in the deep spongy sinus, it is most 

 like WuttaUiua, of which it might be regarded as an exaggeration with 

 a smooth girdle ; but the tail-plate has most affinity with the Mopaloidea. 

 Specimens may be found with many lobes like PliaccUopleura ; but on 

 comparison of many individuals it will be found that the normal ar- 

 rangement is a mopaloid slit on each side, with an angular sinus at the 

 tail, and that the extra slits are extremely irregular and secondary. In 

 Nuttallin-a, the plan, on the contrary, is perfectly regular, and Phacello- 



