Farquhar. — On New Zealand Echinoderms. 197 



bottom without a dozen or more in it, and fishermen often 

 bring them on shore in their nets. The only specimen of 

 E. australe from elsewhere with which I have been able to 

 compare my specimens is one in the Colonial Museum from 

 Fort Jackson, from which they differ considerably in size 

 and shape. My largest specimeDS hardly exceed half the 

 size of that from Australia. They are all relatively broader 

 except very young individuals, and far more depressed an- 

 teriorly. This last difference is very striking and distinct. A 

 comparison of good series of specimens and the results of a 

 detaded examination of the minute structure of both forms is 

 very much needed. 



Arachnoides placenta, Limueus. 



This cake urchin is one of our commonest Echinoderms. 

 It may be found at low water on sandy beaches and on mud- 

 flats in the harbours. Although in Australia it only occurs 

 within the tropics" (north of Wide Bay), in New Zealand it 

 extends as far south as Dunedin — 46° south lat. It is the 

 only Clypeastid known certainly to inhabit the New Zealand 

 seas, for, although Peronclla rostrata has been said to occur 

 here, there is a want of evidence of the occurrence. If the 

 specimen of .1. placenta in the Australian Museum from 

 California was found tbere this species has a very interesting 

 distribution, and will probably be found in many other parts 

 of the Pacific. It has been found fossil in Pliocene formations 

 at Wanganui, Castle Point, and Awamoa. 



Ophionereis schayeri, Midler and Troschel. 



The diameter of the disc is about 20mm., and the length 

 of an arm about six times the diameter of the disc. The arms 

 increase in width from the disc outwards for a short distance, 

 the greatest width without the spines being about 3mm. ; 

 beyond this they remain about the same width, or taper very 

 little, to a third of their length, and thence taper evenly to a 

 fine extremity. The disc is rather tumid, circular with a wavy 

 margin, covered above and below with exceedingly small im- 

 bricating scales, which are larger on the margin of the disc, 

 •especially near the radial shields. The radial shields are very 

 small, irregularly ovate, and distant. The mouth papillae are 

 usually eight to each angle ; they are short, stout, blunt, and 

 close-set, the two at the apex being smaller than the others. 

 The teeth are five m number on each angle, bluntly pointed, 

 vertically compressed, with glassy tips, except the lowermost, 

 which is rounded and smaller than the rest. The mouth- 

 shields are large, and rudely ovate or shield-shaped, and the 



Dr. TUmsa.y's Cat. of Ech. in the Aust. Mu^., p. 54. 



