OF NEW SOUTH WALES. 169 



Sub-Family 2. — Echinanthidje, Agass., 1872. 



Large urchins, petals greatly developed, pillars on acute pro- 

 jections, connecting the two floors, ambulacral furrows straight, 

 auricles two. 



ECHINANTHUS TESTUDINARIUS, Gray. 



This is the large depressed tortoise-like species, so common in 

 Port Jackson, with a very conc.ave under surface and depressed 

 mouth. Petals broad, closed. The anal orifice is near the edge. 

 It is found throughout the Pacific, even as far as California, the 

 Red Sea, and Japan. Is a fossil on the Murray River beds. 



ECHINANTHUS TUMIDUS, N. S. 



I give this name to a large oval swollen urchin which is in the 

 Sydney Museum, and which I have every reason to think came 

 from the coast of N. S. Wales, though there is no precise infor- 

 mation as to its habitat. It is regularly arched, dome-shaped, 

 rising gradually from the edge to a height of nearly half the 

 length. The apex a little flattened, the edge is very thick and 

 rounded, but thinner posteriorly, and a distinct slight depression 

 at each side. The base is flat, but more so posteriorly than 

 anteriorly, so as to bring the transverse small elliptical, marginal, 

 anal opening, with its lower edge level with the base of the test. 

 Tubercles larger below than above, well sunken, and surrounded 

 by rings of milliaries, which also fill up the intervening space. 

 By the side of the milliaries on the lower surface there are many 

 minute pyriform pores. Scrobicular circles of actinal surface 

 wide and deep. I. and A. areas about equal in width. Petals 

 not closed, but gradually diverging to very near the ambitus. 

 Porif. zones gradually enlarging from apical system, being a single 

 row on each side, connected by an oblique groove, and some- 

 times connected from apex to ambitus by a distinct groove ; also 

 a zigzag groove from apex to edge on both I. and A. areas. 

 Actinosome deeply and abruptly sunken. Apical system 

 slightly anterior, small, pentagonal, Gr. pores at the angles, 0. 

 pores between macdreporic body, occupying the central space, and 

 rather scattered in its perforations. Spines small, like Echinus; 



