MUSEUM OF COMPARATIVE ZOOLOGY. 415 



there is a beginning of one, ([iiile pcrceptiljle. The hitter is a proportitjnally 

 wider and Hatter species, with a stronger and more prominent girdle densely 

 set with elongated silvery scales like short stiff gray hairs; these form a pretty 

 fringe at tlie periphery. The sculjttnre follows the pattern of L. cancellatua, 

 but the lateral areas are lesn clcaily defined, the granules are more clearly cut, 

 more regularly arranged, and larger than in any of the species hitherto known. 

 There are twelve gills on each side, reaching forward to about the juiddle of 

 the sixth valve. 



Genus HANLEYIA Grat. 

 Hanleyia tropicalis Dall. 



Plate XXVI. Figs. 8 c, 8 d. 

 Hanleyia tropicalis Dall, Bull. M. C. Z., IX. p. 63, 1881. 



Habitat. Sand Key, in 128 fms. 



No new information or specimens have come to hand since this elegant 

 species was described. 



Family ISCHNOCHITONID^. 



Genus ISCHNOCHITON (Gray) Carpenter, 



Section STENOPLAX Carpenter. 

 Ischnochiton (Stenoplax) limaciformis Sowerbt. 



Chiton limaciformis Sowerby, P. Z. S. 1832, p. 26. Reeve, Conch. Icon. Chiton, 



pi. viii. figs. 42 a- b, 1847. 

 Chiton productiis Reeve, Conch. Icon. Chiton, pi. xvii. fig. 97, 1847. 

 Chiton sanguineus Reeve, loc. cit., fig. 98. 



Ischnochiton limaciformis Shuttleworth, Berner Mitth., 1853, p. 190. 

 Ischnochiton multicostatus Dall, Proc. U. S. Nat. Mas., VI. p. 337, 1883, not of C. B. 



Adams. 

 Chiton {Sterioplax) limaciformis (Cpr.) Morch, Poulsen, Cat. West Indian Shells, 



p. 14, 1878. 



Habitat. Station 10, in 37 fms., lat. 24° 44' N. and Ion. 83° 26' W., in tdie 

 southeastern part of the Gulf of Mexico. Also Key West and other Florida 

 Keys, under stones and among corallines at low water, abundant, Hemphill. 

 Dry Tortugas, Dr. E. Palmer. St Vincent, West Indies, Guilding. Antilles, 

 various collectors. 



This species is also common to West America and Japan, the forms occur- 

 ring in these regions having hardly a varietal difference from each other. It 

 is the largest Ischnoid Chiton of the Antillean region. Ischnoplax multicostatus 

 C. B. Adams agrees in general form, but differs in detail, especially in the 

 armature of the girdle, and belongs in a different section of the genus. Chiton 



