ISCHNOCHITON. 57 



I. LIMACIFORMIS Sowerby. PL 16, figs. 9-16. 



Shell elongated and narrow, elevated, well arched ; buff, gray or 

 greenish, indistinctly marbled with darker, and occasionally blotched 

 with red; longitudinally costulate, not granose ; girdle scales very 

 minute. 



The sculpture upon the central areas consists of fine, close, smooth 

 longitudinal riblets ; these continue upon the lateral areas, becom- 

 ing broader and flat there, and being decidedly waved or irregular 

 on the slope between central and lateral areas. The end valves are 

 sculptured with close, flattened concentric ridges, which are more 

 or less wavy or irregular. The lateral areas are well raised, and 

 are separated by a considerable space at the jugum. The mucro is 

 subcentral and low. 



Interior stained with bright pink and blue-green ; sutural plates 

 well developed; sinus flat, angular, wide; anterior valves with 11, 

 central valves 1, posterior valves 9 slits. Teeth sharp, smooth ; 

 eaves grayish, solid. 



Girdle covered with extremely minute subequal scales. 



Length 35, breadth 12 mill. 



Length 25, breadth 10 mill. 



Florida Keys ; St. Thomas, St. Vincent and West Indies gener- 

 ally ; Central America and Peru; under stones at low water. 



Chiton limaciformis SOWERBY, P. Z. S. 1832, p. 26 ; Conchol. 

 Illustr. f. 38. REEVE, Conch. Icon. t. 8, f. 42. Ischnochiton lima- 

 ciformis SHUTTLEW, Bern. Mittheil. 1853, p. 190. Ischnochiton 

 (Stenoplax) limaciformis Sowb., CPR. MS., and DALL, Blake Gas- 

 trop. p. 415. Ischnochiton multicostatus Ad., DALL, Proc. U. S. 

 Nat. Mus. vi, p. 337, 1883, not of C. B. Adams. Chiton productus 

 REEVE, Conch. Icon. t. 17, f. 97, 1847. Chiton sanguineus REEVE, 

 1. c. f. 98. f Lepidopleurus sanguineus CPR., Maz. Catal. p. 194. 



The West Indian specimens collected by Robert Swift at St. 

 Thomas, and the Peruvian specimens which I have examined are 

 absolutely identical in character except that the former are finely 

 mottled with pink, and one specimen is heavily blotched with crim- 

 son on the second and tail valves (fig. 9). Another tray from the 

 Swift collection contains pale buff examples with faint darker 

 markings. Carpenter has reported the same species, or one very 

 closely allied, from Mazatlan and from Japan. The last certainly 

 requires confirmation. 



