Vol. IX J BERRY— NOTES ON WEST AMERICAN CHITONS 13 



Literature Cited. 

 Iredale, T. 



:14. Some more notes on Polyplacophora. Part I. 

 < Proceedings Malacological Society London, v. 11, pp. 

 123-131, June, 1914. 

 Pilsbry, H. A. 



'92. Monograph of the Polyplacophora. (Lepidopleuridje. 

 Ischnochitonidje, Chitonidse, Mopaliidse). < Manual Con- 

 chology, V. 14, pp. i-xxxiv., 1-350. pi. 1-68, Philadelphia, 1892. 



'98. Chitons collected by Dr. Harold Heath at Pacific 

 Grove, near Monterey, California. < Proceedings Academy 

 Natural Sciences Philadelphia, 1898, pp. 287-291. 

 Thiele, J. 



:09. Revision des Systems der Chitonen. I. Teil. <Zoo- 

 logica, Bd. 22, pp. 1-70, text figs. A-E, pi. 1-6, Stuttgart, 1909. 



5. A New Mopalia From Southeastern Alaska 



The first note in the present series (Berry, :17) was de- 

 voted to a preliminary discussion of a collection of chitons 

 collected by Mr. George Willett in southeastern Alaska, 

 chiefly at Forrester Island, from 1913 to 1916. Some of this 

 material, particularly among the smaller Mopaliidae, I found 

 myself unable at that time to identify to my satisfaction. 

 Certain later material which has since been handed me by 

 Mr. Willett shows that one of the species represented, 

 although one of the most interesting of all the Mopalias, is 

 apparently an undescribed form. A diagnosis is accordinglv 

 oftered below. 



Mopalia egretta Berry 1919 



Pis. 6-7 



Diagnosis: Shell rather small, elongate-oval in outline, 

 moderately elevated, with a sharply carinate, somewhat 

 pinched-in, dorsal ridge; side slopes slightly, though dis- 

 tinctly arcuate; valves slightly beaked. General surface very 

 finely pitted rather than granulose. 



