ACANTHOCHITES-CRYPTOCONCHUS. 35 



are other specimens in the collection of the Geological Survey of 

 Canada, without locality. 



The pustules are rounded, flat-concave topped, crowded, and 

 arranged in distinct series. The dorsal area projects anteriorly 

 beyond the latero-pleural areas ; it is narrow, elevated and longitu- 

 dinally striated, the stride mostly rather indistinct and subgranulated. 

 The white and crimson pattern gives an appearance of great elegance 

 to the valves. 



A. CARPENTERI Pilsbry, n. sp. PL 1, figs. 14-22. 



A series of drawings left by Dr. Carpenter, represent an unnamed 

 new species of Macandrellus, of which he had prepared no descrip- 

 tion. It is so strongly marked, however, that the recognition of the 

 form will be easy. Its prominent features are : (1) the broad, ante- 

 riorly produced, slightly asperulate girdle with minute pore-tufts ; 



(2) the slightly scalloped border of the anterior valve (tegmentum) ; 



(3) the coarse scale-like granulation of the side areas ; and (4) the 

 distinct slitting of the posterior insertion-plate into even, vertical 

 teeth. Length 41, breadth 23 mill. 



Port Elizabeth, S. Africa. 



The figures of detached valves are double natural size. Compare 

 Spongiochiton. 

 A. INVOLUTUS Carpenter, n. sp. PI. 1, figs. 27-35. 



An unpublished species, of which excellent figures by Emerton 

 were prepared for Carpenter. These are reproduced upon my plate, 

 and are sufficient for the recognition of the species, although the 

 sculpture is represented upon the head valve only. All the figures 

 are magnified two diameters. Carpenter gives only the following 

 notes : There are only six stumpy [branchial] leaflets on each side 

 of the tail ; vent inconspicuous ; foot slight and very thin. Head 

 very small, with copious " veil " and neck lappets, outside of which 

 there is a sort of hood around the head, extending backward to the 

 gills (fig. 33), without epidermis, like the foot; outside of all is the 

 large girdle covered inside with granular epidermis." 



Zanzibar (Mus. Comp. Zool.) 



The figures were drawn from alcoholic specimens. 



Section Cryptoconchus Blainville & Guilding, 1829. 



Cnjptoconchus (BLAINVILLE MS. in Brit. Mus. ; BURROW, Elem. 

 Conch., p. 190), GUILDING, Zool. Journ. v,p.28 (1829). GRAY, P. 

 Z. S. 1847, p. 66, 69, 169. Type C. porosus. 



