CRYPTOPLAX. 57 



Length 105, breadth 24, thickness 19 mill, (alcoholic specimen.) 

 Viti Inlands (A. Garrett !) ; Tonga Tabu, Friendly Is. (Q. & G.) ; 



Kandavu, Fiji, (Challenger Exped.) , Dalaguete, Zebu, Philippines 



(Cuming.) 



Cryptoconchus larvceformis BLV. in Burrow, Elem. of Conch, p. 



190, 1815 (no description). Chiton larvceformis BURROW, 1. c., p. 



191, t. 28, f. 2, 3, 4. BLAINV., Manuel de Mai., p. 603, t. 87, f. 6, 

 1825. Cryptoplax larvceformis HADDON, Challenger Polyplac., p. 37, 

 t. 3, f. 12. Cryptoplax larvceformis BLV., Diet. Sci. Nat. xii, p. 124, 

 1818. ADS., Gen. Rec. Moll, i, p. 484. Chiton chitonellus BLAINV., 

 Diet. Sci. Nat. xxxvi, p. 550. Chiton vermiformis BLAINV., 1. c., p. 

 553. Chiton fasciatus QUOY & GAIMARD, Voy. de PAstrol., Zool. 

 iii, p. 408, t. 73, figs. 21-29. Chitonellus fasciatus DESH. in Lam., 

 An. s. Vert, vii, p. 482. REEVE, Conch. Syst., t. 135, f. 3,4; 

 Conch. Icon., f. 2. GOULD, U. S. Expl. Exped., p. 333, atlas, t. 28, 

 f. 429. Cryptoplax fasciata ADS., Genera, t. 55, f. 6, 6a. Chitonellus 

 Icevis REEVE, Conch. Syst. ii, 1. 135, f. 2. Chiton erueiformis SOWB. 

 Gen. Shells, t. 139, f. 5 (1820-1825.) 



Readily distinguished from C. burroivi by the form of the poste- 

 rior valve and the absence of a raised smooth dorsal band on the 

 valves. This latter feature seems to separate it also from C. oculatus, 

 in which, besides, the longitudinal grooves on the sides of the valves do 

 not converge forward. There is also a difference in the profile of 

 the tail-valve, in the spicules surrounding the anterior valves, and 

 in the size. 



On plate 11, fig. 31, 40-43, represent the largest specimen before 

 me. It was collected by Garrett at the Viti Is. Figures 32-34 were 

 also drawn from this specimen, fig. 34' representing a single pore- 

 bunch ; fig. 33 a square mill, from near the posterior valve, and fig. 

 32 a portion of the marginal row of spinelets showing the minute 

 spicules of the base below, the dark-colored spicules of the side of the 

 animal above. This example shows the 18 minute bunches of 

 white spinelets characteristic of the species, although the posterior 

 ones are very minute. Another specimen (fig. 35) is somewhat 

 differently marked, and lacks all pores or pore-bunches. As this 

 example is excellently preserved in spirit, and not wrinkled, the 

 absolute absence of pores can be affirmed with confidence. I can 

 see no differences in the valves between this example and the Viti 

 Island specimens. Part of the dried specimens before me seem to 

 lack pore-bunches, but this cannot be determined with certainty. 



