289 



have broad and smooth dorsal areas. In both forms the ray 

 undulations of the anterior valve are practically absent. Both 

 have coarser spicules and larger tufts than is the case with 

 A. hednalli, but the character of the sculpture closely 

 corresponds. 



The Sydney specimen, given me by Dr. Kesteven, corre- 

 sponds with the Doubtless Bay specimens; the longitudinal 

 .grooving present in hednalli is entirely absent. Also the ray 

 ribbing present in that species in the anterior valve is also 

 absent, or indeterminable. It measures 13 x 7 mm. 



I would mention that in Mr. May's collection is a single 

 specimen, also collected by Dr. Kesteven at Port Jackson, and 

 measuring 11x5 mm., whioh has the longitudinal grooving 

 in the dorsal area, well-defined ray ribs in the anterior valve, 

 and, generally, sculpture corresponding with A. hednalli, 

 Pilsbry, and justifies my recording it as belonging to the New 

 South Wales fauna. 



Acanthochiton exilis, Torr and Ashby. — Add this striking 

 species to the Victorian fauna. Mr. J. H. Gatliff has been 

 good enough to lend me a very fine specimen measuring 

 7 X 3J mm. from Port Phillip, which I think must certainly 

 be referred to this species. 



Macandrellus, Dall. (Bull. Mus. Comp. Zool., xviii., 

 p. 417). — This name was originally suggested by Carpenter, 

 MS., with j\£. plumeus as type, and later was introduced by 

 Dall (in Proc. U.S. Nat. Mus., vol. i., p. 299, 1878), with 

 M. costatus, Ad. and Angas, designated as type. As pointed 

 out by Iredale (Proc. Mai. Soc., vol. xi., part ii., June, 1914, 

 p. 129) this name had to replace that of Pilsbry's Lohoplax, 

 provided Iredale's contention was correct, which reads: ''This 

 species (Chiton violaceus, Quoy and Gaimard) and Ad. and 

 Angas' costatus are undoubtedly congeneric in the strictest 

 restriction." 



I think we are justified in questioning this assumption, 

 for A. costatus, Ad. and Angas, and its allies have a spiculose 

 girdle, whereas violaceus, Quoy and Gaimard, has an ex- 

 tremely broad leathery girdle, which, as far as any specimens 

 T possess are concerned, is quite free from spicules except for 

 the sutural tufts. 



Ire. and May (Proc. Mai. Soc, vol. xii., parts ii. and iii., 

 Nov., 1916, p. 101) state that they anticipated the pos- 

 sibility "that Macandrellus may fall as an absolute synonym 

 of NotO'plaxJ^ 



On carefully examining a number of specimens of A. 



costatus, Ad. and Angas, and A. ruhrostratus , Torr, I find 



that the only specific difference is the fact that in the former 



"the girdle is beset with short, white, evanescent spicules'* 



j2 



