MUSEUM OF COMPARATIVE ZOOLOGY. 415 



there is a beginning of one, quite perceptible. The latter ia a proportionally 

 wider and flatter 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 the periphery. The sculpture follows the pattern of L. cancellalus, 

 but the lateral areas are less clearly 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 middle of 

 'he sixth valve. 



Genus HANLEYIA Gray. 

 Hanleyia tropicalis Dall. 



Plate XXVI. Figs. 8 c, 8 d. 



Hanleyia (ropiccU Tall, Bull. M. C. Z., IX. p. 53, 1881. 



Habitat. Sand Key, in 12t .is. 



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

 species was described. 



Family ISCHNOCHITONID.E. 



Genus ISCHNOCHITON (Gray) Carpenter. 



Section STENOPLAX Carpenter. 

 Ischnochiton (Stenoplax) limaciformis Sowerby. 



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



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

 Chiton productns 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. Mus., VI. p. 337, 1883, not of C. B. 



Adams. 

 Chiton (Stenoplax) 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 die 

 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, hchnoplax multicostatus 

 0. 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 



