239 



Cryptoplax laevis, Lamarck, 1819. 



(Chitonellus lacvis, Lam. An. Sans. Vert., vol. 7, Mollusca, Blainville, pi. 87, f. 5 = 

 Chitonellus lamarcki, Rochebrune, Ashby, I.e.) 



The type was collected by Peron and Lesueur and measures 49X12 mm. 

 In my paper, telling of its rediscovery, occurs the following note : "Nearly the 

 whole of the surface of the shell is eroded, and the girdle is denuded of spicules 

 except that portion commencing opposite valve 7, where the spicules are for- 

 tunately still in evidence. The spicules are very peculiar, being very widely 

 spaced, short, blunt, and rounded, quite distinct from any species I have seen." 



I suggested in the same paper that it might be conspecific with Thiele's 

 C. hartmeyeri, but now, as the result of the present examination of almost, if 

 not all, of the known members of this genus inhabiting Australia and elsewhere, 

 I do not think it likely that the spicules in C. hartfneyeri can ever take the 

 peculiar form of C. laevis, Lam., and therefore its identification must await 

 further elucidation. 



Cryptoplax rostratus, Reeve, 1847. 

 PI. xix., figs. 2, a, b, c. 



(Chitonellus rostratus, Reeve, Conch. Icon., vol. iv., pi. i., fig. 6, May, 1847; C. 

 torresianus, Rochebrune, Bull. Soc. Philom., Paris, p. 195, 1881 ; C. torresianus, Rochebrune, 

 Ashby, I.e., non Chitonellus striatus, Lam., auct.). 



In my paper on the types in the Paris Museum (I.e.) it was shown that the 

 Crytoplax from Sydney, that has been known by collectors as C. striatus, Lam., 

 is not that species, but is conspecific with C. torresianus of Rochebrune. In the 

 hurry of getting that paper completed in time for publication in last year's 

 Transactions, I was unable to refer to my notes on the types one had examined 

 in the British Museum. On turning them up I found that Reeve's name, C. 

 rostratus, antedates that of Rochbrune by many years. The following is my 

 note, dated June, 1922 : "Reeve's type of C. rostratus looks like the Sydney 

 Cryptoplax; probably the locality, Torres Strait, is incorrect." 



The following is Reeve's description: "Chitonellus rostratus, Reeve. The 

 beaked Chitonellus. The valves triangularly oblong, beaked posteriorly, smooth 

 along the summit, grooved on either side, intermediate ridges somewhat grained, 

 olive, dotted with light green, tegament thickly, short, villous-brown, dotted 

 and banded with darker brown. Hab., Raines Island, Torres Strait, Cape 

 Ince." 



In eonclusion. — Mr. Iredale and myself were evidently wrong in our sur- 

 mise that Reeve's locality was incorrect, for Rochebrune's type of C. torresianus 

 is certainly conspecific with the Sydney shell ; this confirms the extension of the 

 range of that species northwards to Torres Strait, and I have a specimen that 

 seems to belong to this form from Twofold Bay, given to me by Mr. Iredale, 

 so it is quite possible that C. striatus and this species may overlap on the Vic- 

 torian border. This species is easily distinguished from C. striatus in that, 

 although very similar in the very juvenile stage, C. rostratus carries this beaded, 

 granulose character into the adult, which C. striatus does not ; also the valves 

 of C. rostratus, even in the fully adult shell, still touch one another. In C. 

 striatus the valves, after the first 4, are more or less spaced in fully adult 

 shells, the spicules in the northern species are slightly more slender, but this 

 difference is but slight. 



Cryptoplax michaelseni, Thiele, 1911. 



PI. xvi., fig. 8 ; pi. xix., figs. 3, a, b, c. 



(Fauna Sudwest Australiens, Polyplacophora, Thiele, 1911, p. 404, pi. vi., figs. 11-17.) 



Another important find of Mr. Worsley C. Johnston's, at Carnarvon, is that 



of a remarkable little Cryptoplax, 7 mm. in length, this species having previously 



