46 



Crypto'plax hartmeyeri, Thiele. — One specimen taken at 

 Yallingup and measuring 12 mm. long was quite new to me. 

 It does not fully agree with Dr. Thiele's figure accompanying 

 his description of the foregoing species (Faun. Sudwest Austr., 

 III., 1911, p. 405, pi. 6, f. 11-17, Shark Bay). The sculpture 

 is more bead-like and the spicules on the girdle are widely 

 spaced and short and thick, quite different from the thickly- 

 set, hair-like spicules of G. gunni, Reeve, or the massed, coarse, 

 curved spicules of G. striatus, Lamark. As Dr. Thiele's 

 specimen was fully three times the size, the bead-like character 

 may have been somewhat impaired. The examination of 

 more material may alter this determination, but, for the pre- 

 sent, I propose to refer the species under review to Dr. Thiele's 

 species. 



Tonicia hulliana, Torr. — This very distinct species has 

 heretofore only been represented by the type specimen, a well- 

 preserved adult shell, collected by Dr. Torr, at Ellensbrook, 

 and described by him (loc. cit., p. 104, pi. 25, f. 4). It was 

 my fortune to find a single specimen of this hitherto unique 

 chiton, measuring, dry, 6'5 x barely 4 mm. It was quite new 

 to me, being apparently smooth and of a delicate pink colour; 

 a few eyes were then noticed in the lateral areas and end 

 valves, and I, at first, thought it must be referred to Dr. 

 Torr's shell, but on turning up the description and figure I 

 found that the sculptural characters figured and described 

 by him were absent, and that almost the only feature present 

 in mine was quite distinct from his, and concluded that, while 

 it certainly was a Tonicia, or rather that division thereof 

 known as Lucilinu, with posterior mucro, it must be an un- 

 described form. Later Dr. Torr, with his usual kindness, 

 forwarded me his type of (Tonicia) Lucilina hulliana, when 

 I discovered that he had overlooked the juvenile features, 

 which consist of a number of pits in the pleural area imme- 

 diately abutting on the anterior margin of the lateral areas, 

 high up on the back. The type has about seven of these 

 clearly visible on most of the valves, if held at the right angle 

 of light. Both specimens are carinated, and I think the 

 statement in the description, "Back rounded, side slopes 

 curved," may therefore be a little misleading. The sculpture 

 of the adult form, correctly described by Torr as "concentric 

 growth-lines running from lateral into pleural and dorsal 

 areas," and the "5 or 6 irregular flattened ribs" in the lateral 

 areas, are absent in the juvenile form, although there is a sug- 

 gestion that these forms of sculpture are about to commence. 

 We have therefore in this species a very excellent example of 

 the wide difference that exists between the sculpture of 



