[81 ll\. H II1TON. 



:, same color. Sutnral plates low ; sinus flat, angular, tinely 

 toutheol. Anterior valve having 10-11, central valves 1, po>terir 

 valve 10 slits; teeth rather >hort ami obtuse, and u.Mially di>tinctly 



belted : eaves rather wide. 



Girdle tinn. compact lv cover. d with regular, solid, oval, >hinii>g 

 scales, which are usually smooth, but frequently are superficially or 



telj striated ii-. 22, 

 Length 85, breadth L'l mill. 

 |.e,, L Mh :'>*. breadth 2-, mill. 



Sitk't iifinl/i to Mnnh-i'ci/, ('of !j'"r/i in. 



Chiton \ Mi DP., Hull. Acad. Sc. St. IV-tcrsh. vi. p. 118, 



l s li. Chiton (PhcenocJiiton, Ilmnm-hiton, Stenosemus) merl 

 Mi 1.1... Mai. Ro.-, p. :U, 125, t. 14, f. 1-3, 184?* J*pfoeAiton 



mertentii II. A. AD., (Jen. Kec. Moll, i, p. -47-">. 1>">4. -J,rj,i'il>,- 

 tM )m-rten*ii CPR., J/*S., and DALL, Proc. U. S. Nat. Mu-. 1 >7 V . 

 p. 8 



This species may be known by the more or less red coloring, the 

 shining convex oval scales of the girdle, which are usually alnnt 

 smooth, and by the strongly developed sculpture. Attention has 

 alr-a'l v been directed to the similarity of the Ch&topleura '/'""/"" 

 >f Cpr. i p. '}} i, which dillers mainly in its spar.-ely hairy girdle. 



- iihrrn examples of this species are larger and more frequently 

 variegated with white than those from the northern part of its 

 range; and the girdle scales seem to be more distinctly striated. 

 They seem to be almost or entirely smooth in mo>t northern speci- 

 mens as far as my material shows; and I do not doubt, that Car- 

 penter's figure (pi. 26, fig. 23) was drawn from a specimen collected 

 north of San Franoisoo. In almost all of the specimens from the 

 smth which I have examined, the scales show a delicate striation 

 \\hen illuminated from the side, or at right angles to the direction 

 of the stri;e. This is shown in figure 2U, drawn by the author from 

 a Monterey specimen. The sculpture of the valves is peculiar ; the 

 ! area ha- diver_'inir line, with smooth intervals. This is 

 always most pronounced on the seconil valve (Hg. lM . the other 

 valves often having the line more nearly parallel, and the intervals 

 not all smooth. This is shown in fi_ r . 25, repir-entiii- a fourth 

 valve; but in smm- specimen- the divergence is even le>s pro- 

 iiMiincrd than in this. The pustules upon the front valve occas- 

 ionally become soldered \> Uto riblets, but those of the tail 

 val mill disti: 



