232 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



No. of Specimens 



11.) /. {Lepidozona) mertensii (Middendorff, 1846) 59 



12.) /. (Lepidozona) zvilletti, new species 36 



13.) /. (Ischnoradsia) triftdus (Carpenter, 1864) ... 6 



Family Mopaliidse. 



Genus Trachydermon Carpenter, 1864. 

 14.) T. flectens (Carpenter, 1864) 10 



Genus Mopalia Gray, 1847. 



15.) M. ciliata (Sowerby, 1840) 4 



16.) M. ciliata wosnessenskii (Middendorff, 1847).. 28 



17.) M. hindsii (Reeve, 1847) 7 



18.) M. lignosa (Gould, 1846) 4 



19.) M. muscosa (Gould, 1846) 1 



20.) M. imporcata Carpenter, 1864 29 



21.) M. sinuata Carpenter, 1864 7 



Genus Placiphorella Carpenter, 1878. 



22.) P. velata "Carpenter," Dall, 1878 2 



23.) P. rufa, new species 15 



Genus Katharina Gray, 1847. 

 24.) K. tunicata (Wood, 1815) 4 



Family Cryptoplacidae. 



Genus Cryptochiton (Middendorff, 1847). 

 25.) C. stelleri (Middendorff, 1847) 4 



622 

 Notes on the Species. 

 1. Leptochiton cancellatus (Sowerby) 



Taken in 20 fathoms at Forrester Island in 1915. This is 

 the smallest chiton in the collection and one of the smallest 

 species we know. 



The rehabilitation of Gray's old genus Leptochiton may 

 occasion some surprise, but perhaps not to those who have 

 felt with the writer that Lepidopleurus Risso, in the sense in 

 which it has been commonly used, is little but an amorphous 



