ACANTHOCHITES. 17 



yellowish ; often yellowish or reddish on the dorsal line ; occasion- 

 ally greenish. The spines on the raantle vary from green to brown. 

 Green is the more common color in the north, while brown appears 

 to be universal in Otago. 



It is by no means certain that but one species of Acanthochites 

 exists in New Zealand. Especial attention should be given to the 

 form and denticulation of the tail valve of specimens from different 

 New Zealand localities, in order to settle this question. Specimens 

 before me seem to indicate a second species, but they are not per- 

 fectly preserved. 



A. CARINATUS Adams & Angas. 



Shell elongated ; valves moderate, strongly carinated, beaked 

 behind ; whitish maculated with reddish-brown ; very closely pustu- 

 lose, in the middle smooth and black-brown ; lateral areas indistinct. 

 Girdle beset with minute white spicules, and bunches of pale spicules. 



Length 30, breadth 16 mill. (A. & A.} 



Port Jackson, New South Wales (Angas.) 



Acanthochites carinatus AD. & ANG., P. Z. S. 1864, p. 194. 

 ANGAS, P. Z. S. 1867, p. 224. 



A single specimen was collected by Angas. Mr. E. A. Smith has 

 expressed the opinion that it is the same as the European species A. 

 discrepans (Proc. Zool. Soc. Lond. 1891, p. 392), but this view needs 

 confirmation, being founded probably on a study of the external 

 characters only. 



A. ASBESTOIDES Carpenter. PL 2, fig. 55. 



Shell small, greyish-brown, with a pale line on each side of the 

 middle of the central valves, slightly converging behind, leaving a 

 dark-wedge shaped space between them. Surface covered with a 

 coarseish granulation, the granules being somewhat flattened and 

 those at the vertex of the central valves rather smaller than the rest. 

 ( The lateral areas are not defined in these valves ; the posterior 

 curved margins are produced in the middle, at times almost forming 

 a right angle; their insertion plates are large, thin, produced ante- 

 riorly with a very slight notch quite close to the hinder margin on 

 each side ; the sinus between them in front is deep and arcuate. 

 The first valve has a straighter posterior margin than the succeeding 

 ones, and a semicircular outline in front ; the lamina of insertion is 

 rather deep, thin, feebly striated exteriorly, and interrupted by five 

 very small subequidistant notches. The last valve is conspicuously 

 2 



