462 CENSUS OF THE MARINE MOLLUSCA OF TASMANIA, 



been made; the crenulated margin belongs to V. Diemoiensis, as 

 indicated by its radial costation. However, V. hrevis is not 

 known to Tasmanian collectors, but if Tasmanian it may be a 

 deformed example of V. ohesa. * 



Mytilicardia aviculina, Lamarck. 



The type came from King Island and was figured by Delessert 

 in 1841, and the study of that figure does not permit of hesitation 

 in regarding excavata and Tasmanica as the same as it. M. 

 excavata is based on a young shell, having rose-coloured spots 

 chiefly on the large post-medial ribs. M. Tasmanica is based 

 also on a small-sized specimen; "gaping below" is incorrect, and 

 the distinction " ribs smooth instead of lamellar projecting scales" 

 is also incorrect; M. Tasmanica \'^ perhaps more dilated behind, 

 and M. excavata shows a tendency of the larger ribs to become 

 broader as compared with M. Tasmanica; but these differences 

 are individual rather than racial. 



Modiolarca Tasmanica, Beddome. 



If Miss Lodder's specimen, which is fignred on p. 439, is rightly 

 named and there is no reason for doubt, then the species is an 

 interesting addition to a genus known hitherto by three species, 

 all of the Southern Hemisphere, two of which are circumpolar. 

 M. Tasmanica is most allied to M. trapezina, Lamarck, from 

 which it differs by the insinuation of the antero-ventral margin, 

 by the attenuated and prolonged front margin, and by the pos- 

 session of two teeth on the hinge-line (E. A. Smith describes the 

 hinge of M. trapezina "with a small tubercular tooth in each 



valve "). 



Pecten actings, Petterd.* 



This species has the form and general ornament of /'. tigris, as 

 represented by Philippi's figures of that Lamarckian shell. The 

 radial groups are about twelve, flatly convex and truncatedly 

 defined; the costal threads in each group are usually three, and 



* To this species I should refer P. hednalli, Tate; but as my late colleague 

 was not consulted on this point the synonym is not inserted in the text. — 

 [W. L. May]. 



