60 ISCHNOCHITON. 



and /. magdalenensis is that the latter lias radsioid valves and coarser 

 girdle scales. ( 'arpenter's description is given above, and the fig- 

 ures represent the type specimen. 



The foot is produced forward, and the gill row is short at both 



I. A i. ATCS Sowerby. PI. 16, figs. 1-5. 



Shell much elongated, narrow, elevated, rather thin. On a light 

 Mi-shy hut!' or greenish ground it is delicately marbled and mottled 

 with olive or olive-green. The sculpture consists of longitudinal 

 close, narrow ridges, which are finer on the dorsal ridge, and clump 

 to an irregular granulation on the lateral areas and terminal valves. 

 The lateral areas are decidedly raised ; the jugal area is divided 

 from the pleura by a change in sculpture, which becomes coarser 

 and more or less divaricating, sometimes forming a cellular pattern 

 at the edges of the jugal area and on the slopes of the lateral areas. 



Interior rose-pink, rarely almost white; anterior valve having 9, 

 central 1, posterior valve 9 slits. Teeth sharp, eaves moderate, 

 solid. Sutural plates large, rounded ; sinus very deep, narrow. 



<iirdle wide, thin, covered with fine, even, short, striated solid 

 scales, 



L.-ngth 57, breadth 16 mill. 



Length 40, breadth 16 mill. 



Islands of Siquijor and Zebu, Philippines, under stones at low 

 water. 



Chiton alatus SOWERBY, P. Z. S. 1841, p. 61. RVE, Conch. Icon. 

 t. 8, f. 45.Ishnochiton alatus GRAY, P. Z. S. 1847, p. 127, and 

 /. n/tu8 Gray, Guide, p. 1 82. Stenoplax alata CPR. MS. 



The solid, deeply striated scales of the girdle are very character- 

 i-tic, as is also the sculpture. The pattern of color is an indefinite 

 and variable mottling. Figures 3, 4, 5 are drawn from a typical 

 specimen received from Sowerby. Figures 1, 2 are from draw- 

 ing made for Carpenter, and represent the scales as much more 

 elongated, and the head valve as less emarginate. 1 am disposed 

 to believe that this last peculiarity is a mistake. 



The sole is produced forwa rd as far as the month; head Me>hy : 

 veil copious, neck lappets long. Gills about one valve's luvadth 

 removed from neck and the same at tail. Vent inconspicuous. 

 Foot fleshy, projecting. 



