Lorica.] AMPHINEURA. 47 



Type in the British Museum ; of C. rudis, Hutt., in the Dominion 

 Museum, Wellington. 



Hal>. Whale Rock buoy-moorings, 20 fathoms, one specimen 

 (Captain Bollons) ; Channel Island, Hauraki Gulf, 25 fathoms, one in- 

 termediate valve ; Dusky Sound, 30 fathoms (R. Henry). Australia. 



Remark. The specimen in the Dominion Museum, locality not 

 stated, may now safely be considered as having been obtained some- 

 where in New Zealand. 



Genus 6. ONITHOCHITON. Gray, 1847. 



Onithochiton, Gray, P.Z.S., 1847, 65, 68, 169. Type : Chiton undulatus, 

 Q. & G. 



Valves exposed, polished, beaked, with indistinct lateral areas ; 

 eyes present and disposed in a ray on the forward part of each lateral 

 area and in numerous rays on the anterior valve. Interior porcel- 

 lanous ; sinus denticulate, angular ; insertion plates pectinated out- 

 side, that of the first valve with 8 slits, median valves 1 slit ; posterior 

 valve depressed, triangular, with posterior terminal and marginal 

 mucro, the insertion plate reduced to a low, smooth, and narrow 

 callus. Girdle leathery, rendered velvety by very minute chaffy hairs. 

 (Pilsbry.) 



The species are distributed from the Cape of Good Hope to New 

 Zealand. 



KEY TO SPECIES. 



a. Lateral areas and anterior valve smooth or radially sculptured ; 



central areas smooth. 



b. Lateral areas smooth or with 4 or 5 low subgranose riblets undulatus. 

 bb. Lateral areas closely sculptured with close subgranose 



striae . . . . . . . . - - - - semisculptus. 



00. Lateral areas having concentric sculpture ; central areas or 



pleura with forwardly converging sulci . . . . nodosus. 



1. Onithochiton nodosus, Suter, 1907. Plate 5, fig. 4. 



Onithochiton nodosus, Suter, P. Mai. S., vii, 297, f. 4 in text. 



Shell small, elongately ovate, shining, flesh-colour, variegated with 

 white and brown, lateral areas with nodulous ribs. Anterior valve 

 with about 20 radiate nodulous riblets, crossed by 4 concentric fur- 

 rows ; about 14 radiate rows of minute silvery eyes. Intermediate 

 valves slightly beaked, with the jugum sharply rounded ; central areas 

 minutely punctate, longitudinal sulci in front of the lateral areas, 

 short near the centre, but extending nearly the whole length on ap- 

 proaching the margins ; several transverse furrows extend over the 

 central areas. Lateral areas scarcely raised, with 3 nodulous ribs, the 

 2 posterior ones close together ; sutures slightly crenulated ; one row 

 of eyes between the first and second rib. Posterior valve with the 

 mucro terminal, minutely punctate, a concentric marginal row of 



