NO. 2223. CHITONS FROM THE NORTHWEST PACIFIC— BERRY. 15 



Family CHITONIDAE. 



Genus CHITON Linnaeus, 1758. 



CHITON, species. 



Plate 8, fig. 6. 



A small specimen collected between tides at Aikawa, Rikuzen 

 [S. S. B. 120], Cat. No. 215634, U.S.N.M., can not be identified with 

 any of the described Japanese Chitonidae. It is quite likely new, 

 and the accompaning illustration was prepared in the expectation of 

 so treating it. Unfortunately the specimen seems at one time to 

 have suffered immersion in formalin or some other decalcifying 

 medium. At any rate, the valves proved so soft and subject to 

 disintegration upon removal that their characters could not be made 

 out with enough accuracy to justify naming the specimen. When 

 the species is later rediscovered it may perhaps be recognized by the 

 figure. 



EXPLANATION OF PLATES. . • 



Plate 1. 



Fig. 1. Leptochiton diomedeae Berry [95], dorsal aspect of first, third, and last valves 

 of type specimen; X 8. 



2. Leptochiton diomedeae Berry [95], entire animal in ventral aspect; X 3. 



3. Leptochiton diomedeae Berry, dorsal view of portion of girdle of same speci- 



men; drawn from a mount in balsam; X 28. 



4. Ischnochiton (Ischnoradsia) albrechti Schrenck [83], dorsal view of portion of 



girdle; drawn from a mount in balsam; X 7^. 



5. Ischnochiton (Ischnoradsia) albrechti Schrenck, a few scales from the same 



preparation as fig. 4 seen in greater magnification; X 27. 



6. 'Ischnochiton (Ischnoradsia) hakodadensis Carpenter [85], dorsal view of por- 



tion of girdle of a specimen from Hakodate; drawn from a mount in 

 balsam; X 10. 



7. Ischnochiton (Ischnoradsia) hakodadensis Carpenter, a few scales from the 



same preparation as fig. 6 seen in greater magnification; X 27. 



Plate 2. 



Fig. 1. Leptochiton diomedeae Berry [95], exterior view of first, third, and last 

 valves of type; camera drawing; X 9. 



2. Interior view of same, same scale. 



3. Anterior view of third valve; same scale. 



4. Isolated girdle scales from same specimen, the four larger from the dorsal, 



the four smaller from the ventral surface of the girdle; camera drawing 

 from a mount in balsam; X 163. 



5. Portion of girdle margin of same specimen, seen from above; camera out- 



line from a mount in balsam ; same scale as preceding. 



6. Teeth from radula of same specimen; camera drawing from a mount in 



balsam; X 163. 



