' : 'i .1 i i: \. 



suture. The valves MIT iniiiiitclv .-culpmred \vitli very minute 

 granules in lin-> which diverge -li-htly at the jiiiriini, more upon 

 tin 1 >ide- ol' the central area-, divaricate on tlie horder ln-t 

 central and lateral areas, and an- radiating upon the liiti-ral ai 

 and tenninal valves. The iimho of the tail valve i> low, -omeuhal 

 anterior. 



Interior white with a brown stain at the back edire of each valv-. 

 Anterior valve having lon^- insertion plates which are di.-tinctlv 

 crennlated outside, ami have !)-!() slits, central valves with 1 -lit, 

 post, valve with 7~V slits. Sutural plates very broad, connected 

 across the sinus hy a narrow plate; eaves narrow, .-hort, 



Length 38, breadth 20 mill. 



Lima, Peru; Chili; to Oij>r 



Chiton periivianus LMK., An. s. Vert, vi, p. 321 ; ed. Dh., vii, p. 

 491. Barnes, Amer. Jour. Sci. vii, p. 10, t. 3, f. 2. SOWB., Conch. 

 Illustr. f. 44. KI:I:\ i: Conch. Icon. f. 50. Chaetopleura peruviana 

 Lm., SHUTTLW., Diagn. n. Moll. nr. 4, p. 07. \{<>< \\ i.m; ., Moll. 

 Cap Horn, p. 1-^). Acanthopleura peruviana Lm., TAP. CAN., 

 Viag. Magenta, p. 77. 



This form is readily known by its girdle covering and sutural 

 fringes of long black hairs. The sutural plates are strongly devel- 

 oped, slightly recalling Leptoplax. The hair is crisp and coarse, 

 like that of a horse's tail. The gills extend forward to the head. 



C. HENNAHI Gray. PI. 12, figs. 47, 48, 49 ; pi. 17, fig. 39. 



Shell oval, rather depressed, dorsal ridge obtuse, side slopes 

 nearly straight. Color variable, but generally either reddish-brown 

 marked with red, or greenish-white marked with brown ; surface 

 smooth to the naked eye. Girdle leathery, covered with short hairs, 

 which may readily be rubbed off. 



The median valves are about four times as wide as long; the 

 lateral areas are only weakly indicated ; the tail valve is depre>- d, 

 with the slightly prominent umbo in front of the middle, the pos- 

 terior slope concave. The sculpture consists of closely beaded ti in- 

 separated threads, which are longitudinal on the central, radiating 

 on the lateral areas and end valves ; under this may be seen an 

 excessively fine, close shagreening of the whole surface. 



Inside white, each valve marked with brown under the beaks. 

 Sutural plates of equal width from the outer angle of the valve to the 

 rather shallow sinus. Ant. valve having 13, central valves 1. po>t. 



