ACANTHOPJ.EURA. 91 



except by color- stains, the ribs converging and meeting (y\-like) 

 forward ; central areas having about 14 sharp, rather distant 

 riblets on each side, the intervals quincunically granulated ; lateral 

 areas not much raised and small, the diagonal rib running out to the 

 posterior end of the corner, the sutures deep and rounded ; diagonal 

 rib nodulous; sutural rib much stouter, with larger grains, the space 

 between having metallic dots, [eyes], and often grains intercalated. 

 Posterior valve having the mucro elevated at a slightly obtuse angle 

 one-fifth of the valve's length from the posterior end. Interior: 

 anterior valve with 8, median valves 1-1, posterior 10 slits ; teeth 

 rather conical and thrown forward in the tail valve; and viewed 

 from behind the tooth-row curves upward in the middle, and the 

 teeth are smaller and closer there ; the teeth are sharp, and slightly 

 pectinated outside ; the anterior and side teeth are smooth. Sinus 

 flat and deep, with about 16 teeth. Girdle having a few scattered 

 hairs, densely and very minutely papillose. 



Length 20, breadth 11 mill. ; divergence 118°. 



This species belongs to the group of T. suezensu, nigropunctata 

 and fortilirata (vol. xiv, p. 206), characterized by the posterior 

 mucro, strong longitudinal sulcation of the central areas, and the 

 slightly asperulate or downy girdle. 



Genus ACANTHOPLEURA Guild. (Vol. XIV, p. 2 J 3). 



Add to synonyms : Rhopalopleura Thiele, Das Gebiss ii p. 373 

 for " Chiton aculeahis L." 



A. spiNiGER Sowb. (Vol. XIV, p. 221). 



The citations of Angas and Tappa rone-Can efri of New South 

 Wales localities for Chiton "piceus" (vol. xiv, p. 226) refer to 

 Idolophura gaimardi. 



Undetermined species. 



AcANTHOPLEURA RAWAKANA Rochcbr. Shell ovate, wide, gray, 

 with spots and lines of blue and red, and scattered black dots. 

 Anterior valve and posterior part of the posterior valve concentric- 

 ally pustulate. Intermediate valves having the lateral areas multi- 

 squamose; central areas very minutely pitted. Marginal ligament 

 rather wide, having acute red spines. Length 19, breadth 12 milL 

 (Rochebr. in Bull. Soc. Philom. 1881-'82, p. 195.) 



Rawak, Papua. Rare. Mus. Paris. 



