Callochiton.} AMPHINEURA. 13 



of the mucro. Interior pink ; sinus rather broad, shallow ; inter- 

 mediate valves with 4 slits on each side. 



Length, 22 mm. ; breadth, 9 mm. Divergence, 83. 



Type in the Dominion Museum, Wellington. 



Hab. Near Stewart Island, in about 15 fathoms. 



Remarks. A specimen found on oysters by Mr. C. Cooper, of Auck- 

 land, and kindly presented to me, was used for the description and 

 figures. As I did not want to disarticulate the only specimen, the num- 

 ber of slits in the terminal valves still remain unknown. The habitat 

 of this species was hitherto unknown. 



2. Callochiton platessa, Gould, 1846. Plate 3, fig. 7, a-d. 



Chiton platessa, Gould, P. Bost. S.N.H., ii, 143 ; U.S. Expl. Ex., 320, f. 434, 

 434a. Callochiton platessa, Gould, Man. Conch. (1), xiv, 49, pi. 10, f. 1-5 ; 

 P. Mai. S., ii, 184; T.N.Z.I., xl, 374. Chiton crocinus, Reeve, Conch. 

 Icon., pi. 22, f. 146. Callochiton crocinus, Keeve, Man. Conch. (1), xv, 

 67, pi. 10, f. 7. Chiton versicolor, Angas, P.Z.S., 1852, 92. pi. 16, f. 5. 

 Leptochiton versicolor, Angas, P.Z.S., 1867, 223. 



Shell oval, surface delicately shagreened, no radial sculpture; 

 colour orange or yellowish-white, with end valves and part of the 

 central valves orange. Anterior valve with a few indistinct concentric- 

 lines of growth. Intermediate valves rounded, beaked, the central 

 areas with fine transverse lines, lateral areas elevated, with a number 

 of distant low concentric ridges, very rarely an indication of a few 

 radiate furrows. Posterior valve with the central area distinctly 

 separated from the posterior area by a straight transverse line, pos- 

 terior area with a few concentric growth-lines ; mucro median, very 

 low, posterior slope but slightly convex. Girdle with delicate flat 

 elongated scales. Colour very variable, orange with yellowish longi- 

 tudinal bands, alternating orange and white spots on the sutures, or 

 head and tail valve orange, the latter with a white triangular spot 

 in the middle of the central area, the intermediate valves yellowish 

 or reddish white, with orange spots on the beaks ; there are minute 

 black dots (eyes) present, which are absent from the central areas ; 

 the girdle brownish, with a few small white flecks and 5 large white 

 spots, 4 very large spots extending from the first and sixth suture to the 

 edge of the girdle. Interior : Anterior valve with 16 slits, intermediate 

 valves with 3 slits on each side, posterior valve with 14 slits ; teeth 

 solid, bifid or 3-shaped, propped outside ; eaves very spongy, simple, 

 short ; sinus small, wide ; sutural plates united. 



Length, 19 mm. ; breadth, 13 mm. Divergence, 120. 



Type in the U.S. National Museum, Washington. 



Hab. Port Pegasus, Stewart Island, 18 fathoms (Captain Bollons) : 

 Lyall Bay (W. H. Webster) ; Shag Point (Iredale). Australia. 



Remarks. There is one specimen, locality unknown, in the Do- 

 minion Museum, Wellington. This is one of our very rare species. 



