274 CALLISTOCHITON. 



It seems to resemble the unfigured I. lateritius Shuttlew. in color 

 and somewhat in sculpture; but Shuttleworth says of his species "valvis 

 terminalibus subconeentrice lineatus punctatisque ; mediis non carin- 

 atis," etc., and this in no way agrees with the species described 

 above. 



The type is in the collection of the Academy. 



C. ANTIQUUS Reeve. PI. 59, figs. 29, 30, 31, 32, 34, 35. 



Shell oblong-elliptical, moderately convex, obtusely carinated, the 

 side-slopes convex ; of a uniform soiled buff, or stained with reddish 

 along the back ; sometimes tinged with olive-green. 



Valves not beaked. Lateral areas composed of two strongly 

 elevated ribs, bearing compressed grains, the posterior rib wider, its 

 grains denticulating the suture. Central areas having a honey-comb 

 reticulation near the beaks, on the sides changing into fine longitu- 

 dinal riblets with minutely latticed intervals. Anterior valve hav- 

 ing 11-12 very strong, rather narrow and acutely granose ribs. 

 Posterior valve depressed, sloping backward from the front margin, 

 the mucro depressed, slightly in front of the center ; the posterior 

 area having 8-9 strong granose ribs. 



Interior bluish-white, sutural plates low, rounded, separated by a 

 broad shallow sinus. Anterior valve having 9, central 1, posterior 

 9 slits, corresponding to the external ribs; teeth smooth, rather 

 sharp, curved and concave outside as usual in Callistochiton. Eaves 

 rather narrow. 



Girdle wide, thin, leathery, compactly covered with very small 

 convex and apparently smooth brown scales, having light colored 

 larger scales mingled among them (fig. 34.) 



Length 17, breadth 10 mill.; divergence 110-120. 



Port Molle, Queensland (Coppinger), Port Jackson, N. S. Wales 

 (Angas, Brazier, Challenger.) 



Chiton antiquus REEVE. Conch. Icon., t. 25, f. 169 (poor). 

 Lepidopleurus antiquus ANGAS, P. Z. S. 1867, p. 223. Callistochiton 

 antiquus CPR. MS. and HADDON, Challenger Polyplac., p. 20. 

 Chiton (Callistochiton) antiquus E. A. SMITH, Zool. Coll. 'Alert' p. 

 79. Callistochiton sarcophagus CPR., MS, 



This species has the same style of honey-comb or netted sculpture 

 toward the beaks that C. pulchellus and C. shuttleworthianus show. 

 A specimen in which the number of ribs on the head valve is 

 increased by splitting to 17, and on the tail valve to 16 is on record ; 



