MOLLUSCA — IIEDLEY. 



351 



M A L A X T S, Deshayes. 

 OMALAXIS MEKIDIONALIS, sp. nov. 



(Fi^. 74.) 

 Station 13. 



Shell small thin rotate, flat above, shallow concave beneath, 

 sides perpendicular. Colour 

 white. In its broken state 

 there remain two whorls and 

 the protoconch. Whorls almost 

 square in section, with a keel 

 projecting at the upper and 

 lower corners. Sutures chan- 

 nelled. Sculpture : above, the 

 upper outer keel stands up from 

 the surface and is constituted 

 by a double bead row ; latterly 

 two smaller beads intervene 

 between larger ones. A single 

 narrow bead row runs along the 

 inner margin close to the suture. 

 On the base a single broad 

 elevated bead I'ow forms the 

 outer keel and a narrower row 

 runs along the inner margin. 

 On the side are three evenly 

 spaced raised threads. The 

 space between the bead rows is 

 transversely striated by growth 

 lines. Protoconch tilted, but 

 not sufficiently so to conceal 

 the whorls either from above or 

 from below. Major diam , 4*5 

 mm. ; minor diam., 3 '6 mm. ; 

 height, 1-25 mm. 



The "Thetis" took a very young specimen of an Omalaxis, a 

 genus heretofore unknown in Australia. As it was too small to 

 deal with, I have used for my type a broken specimen of an 

 Omalaxis, perhaps but not certainly the same species, which v/as 

 previously dredged in Port- Stephens. 



From 49-50 fathoms oif Cape Three Points. 



Fig. 74. 



