158 THE PROCEEDINGS OF THE LINNEAN SOCIETY 



vertical row in the median space. Coronal plates loosely 

 covered by minute tubercles and few milliaries. In the A. space 

 there is one irregular central vertical row of small tubercles, with 

 one exterior vertical row of tubercles somewhat larger, from the 

 base of which smaller tubercles running obliquely, separate the 

 arcs of pores. Porif. zone formed of arcs of five to eight pairs, 

 more or less closed above the ambitus. Cuts not deep, but broad 

 and well defined. Membrane thin, covered by few very distinct 

 elliptical plates. It is larger than the last species, and the spines 

 longer. It is not common, and found generally in N.B. tropical 

 Australia, but I have seen a specimen from Port Stephens, and 

 another from New Zealand, Neither this species nor S. armiger 

 was found by the " Chevert," nor are there specimens in the 

 Macleay or Sydney Museums. 



Genus 6. — Sph^rechinus, Desor, 1857. 



Test thick, tubercles of uniform size, imperforate, not crenu- 

 late, numerous, closely packed together on both areas. Actinosome 

 decagonal, with deep cuts. Membrane thin, with four prominent 

 plates. Pores in closed arcs of four to eight pairs. 



SphjErechinus Australia, A. Agas. 



Colour of test violet, with tubercles of dull green, spines 

 short, tolerably stout, violet at base with greenish tips, old speci- 

 mens, but when fresh the color is entirely a blue purple. In the I. 

 space there are six to eight vertical rows of primary tubercles 

 near the median space separating the principal rows, closely 

 packed secondaries fill the rest of the coronal plates. The most 

 prominent row of primaries is half way between the median line 

 and porif. zone. Anal system large. The porif. zone narrow. 

 Pores arranged in arcs of three towards the exterior, well separ- 

 ated from the inner fourth pair, which is quite hidden among the 

 tubercles, forming almost an independent vertical row. 



Not common. Often found, but stripped of its spines. It is 

 sometimes washed ashore on the sandy beaches of the South 

 Australian coast. Found also in Bass's Straits, King's Island, 



