THE NAUTILUS. 



Vol. XXXII. JULY, 1918. No. 1 



NOTES ON THE GENUS TRACHYDERMON CARPENTER. 



BY WILLIAM HEALET DALL. 



Iredale has already called attention to the two names for 

 Chitons by Gray in 1821. A little fuller discussion of the 

 consequences of the adoption of Gray's name Lepidochitona 

 seems desirable to make the situation perfectly clear. The 

 synonymy which is pertinent is as follows : 



Lepidochitona, Gray, London Medical Rep., XV, p. 234, 1821. 

 Chiton marginatus (Penn&ut, = cinereus L., not of Mon- 

 tagu). 



Stenosemus Middendorff, Malae. Boss. 1, pp. 103, 109, 117, 122, 

 1848; (1st sp. C. marmoreus Fabr.). 



IschnocMton sect.tt, Gray, Guide Moll., p. 182, 1857 (Chiton 

 marginatus} . 



Trachydermon Carpenter, Suppl. Rep. Br. Assoc., 1864, p. 

 612 (Chiton dentiens Gould) ; ibid., p. 649: Bull. Essex 

 Inst., p. 153, 1873 (Chiton ruber (L.) Lowe, not of 

 Spengler) . 



Craspedochiton G. 0. Sars, Moll. Reg. Arct. Norv., p. 114, 

 1878 (Chiton marginatus Pennant, = cinereus L., not of 

 Montagu). 



Leptochitona Pilsbry, Man. XIV, p. 150, 1892 (err. typ.). 



Section Tonicella Carpenter. 



Platysemus Middendorff, (part) Mai. Ross. 1, p. 98, 1848 (C. 

 submarmoreus Midd.). 



