22 ACANTHOCHITES. 



(4) Species of the West Indies and West America. 

 A. spicuLOSus Reeve. PI. 13, figs. 60, 61, 62. 



Shell somewhat elongately ovate, valves semilunar, rough through- 

 out; blackish-brown; ligament horny, furnished with thick tufts of 



bright olive glassy spicules. {Reeve.) 



West Indies. 



Chiton s2ncuIosa Reeve, Conch. Icon., t. 9, f. 47 (Feb., 1847). — 

 Acanthochiton spiculosus Cpr. MS. 



This form is probably merely a dark specimen of the species after- 

 ward described by Reeve as C. astriger. Mr. E. A. Smith has 

 expressed his belief that this is the case, in Journ. Linn. Soc. Lond. 

 XX, p. 497. 



Var, ASTRIGER Reeve. PI. 13, figs. 55, 56, 57. 



Shell oblong, rather depressed, not carinated. Valves variously 

 colored, green or olive-green, usually tinged with brown on the sides, 

 often marked with rather wide white stripes at the sides. 



The valves are generally more or less encrusted. Dorsal areas 

 narrow, slightly raised at the edges, convex and shining, marked by 

 delicate longitudinal strife and transverse growth-lines. Latero- 

 pleural areas very minutely and evenly granulated, the granules 

 rounded. Posterior valve small, its tegmentum slightly longer than 

 broad, the mucro near the posterior margin. 



Interior blue-green; sinus wide, deep and subangular; sutural- 

 laminee large, blue-green. Insertion-plate of the posterior valve visible 

 behind, as well as at the sides of the tegmentum when viewed from 

 above ; posterior outline bilobed, having a median sinus, and slits 

 outside of the lobes. 



Girdle minutely velvety, olive-green, having 18 very large con- 

 spicuous tufts of greenish-white spicules ; the periphery bearing a 

 fringe of spicules. 



Length 20-22, breadth 9 mill. 



Florida Keys to Barbados, West Indies. 



Chiton astriger Reeve, Conch. Icon., t. 18, f. 109 (April, 1847). 

 — Phakellopleura (Acanthochites) astrigera Shutt., Bern. Mittheil. 

 1853, p. 79. — Acanthochiton astriger Dall, Bull. 37, U. S. Nat. Mus. 

 p. 174. — Chiton {Acanthochiton) astriger Smith, Journ. Linn. Soc. 

 Lond. XX, p. 496 (1890.) 



Additional localities are : Guadeloupe (Sivift) ; St. Thomas 

 {Blaitner); Tortugas {Dall), and Fernando Noronho {Ridley and 

 Ramage.) 



