LEPIDOPLEU1 ."i 



isolated puMiilr-, alxoliitcly irn-L r ular in di-l ril.ul i< : 

 same .-!/ on the mucro ;in<l eUr\\h -re. N.\\l 

 Iille>. The aicll of tin- back is | >eci 1 1 ia ll y P>und. the lat- : 

 not rai^-d ami barely di>tiniMii>hai)le. The girdle seem 

 I have compared typical examples. 



L. ooncmnttt Gould, from the types, ifl of i diilen-nt color, and 

 has a much M router and different sculpture like line- of i 



L. inft'nir.rii.'S ( 'arpenter and var. rui/nln.* ( 'pr., are more like 

 cinnii*, hut di-tin^-mslied from either by the peculiar ^irdl- 

 with sul>e<|iial scales. 



L. nexn* ('arpenter more nearly resembles c.ancellatns but the 

 sculpture is of separate, not lapping, rounded rhomboidal pu>n 

 the mucrones are much more pronounced, and the white ground i- 

 prettily marbled with black and gray inherent coloration. The 

 name cancellattu is a misnomer, since it is only in certain lights that 

 any trace of reticulation can be observed faintly. The young are 

 flatter than the adults. It bears no resemblance to L. asellus, with 

 which Middendorff united it, probably without a comparison. 



L. arcticus of Sars seems to be a finely grown variety of this spe- 

 cies, if one may judge from the figures; at least, no differential 

 characters are given which seem to be of a permanent character, 

 and not subject to variation within the limits of a species. 



The gills occupy a space corresponding to the posterior quarter 

 of the foot ; there are about eight or ten on each side. The 

 mantle edge is plain and thick. The veil is plain. The muzzle is 

 rounded, with a little papilla at the posterior corner on each side 

 (Dall.) 



L. ARCTICUS Sars. PI. 3, figs. 59-63. 



Shell subdepressed, dorsal keel obsolete, lateral areas little con- 

 spicuous. Posterior valve smaller than the anterior, subrhom- 

 boidal, roundly produced in front. Median plates throe tim- 

 long as broad, the front margin truncate in the middle. Surface of 

 the valves nearly smooth, indistinctly granulose. (Sars.) 



Length 12 mill. 



Spitzbergen, Greenland, Vadso and Finmark, 20-10* 



Lepidopleurus arcticus SARS, Moll. Reg. Arct. Norv. p. 11-, t. 7, 

 f. 7. Chiton aretiew JEFFREYS, P. Z. 8. 1882, p. 668. 



Dall, judging from the description and figures, considered tl 

 form of L. cancellatus. Jeffreys, who found the - D the 



