366 



anal and sexual plates and spines are not preserved in our 

 specimen. 



The origin of this species is not precisely ascertained. 1 

 found its fragments among East Indian shells, and reconstructed 

 the specimen which I have placed in the cabinet of the Society. 



3. PsABiMECHiNus ASTEROiDEs Girard. The external series 

 of tubercles of the interambulacral spaces are much larger than 

 others and form a prominent star-like figure which constitutes 

 the chief character of this species. Its general form is circular 

 and very depressed. From New Zealand. It belongs to the 

 cabinet of the Society. Another species of the same genus, but 

 smaller and spheroidal and not yet described, was found on the 

 shores of that Island by Quoy and Gaimard in 1829 ; so that 

 there are two species of true Echini to be added to the New 

 Zealand fauna. Hitherto only two species of Heliocidaris, one 

 of Laganum and one of Echinoneus were on record. 



4. EcHiNOMETRA NiGRiNA Girard. Small species, subovate, 

 very much depressed, nearly flat above. The interambulacral 

 spaces have twice the width of the ambulacral. There are five 

 or six pairs of pores in the ambulacra. The tubercles in the 

 ambulacral spaces are smaller than those of the interambulacral, 

 and form only a double very close series. In the interambula- 

 cral spaces there is also a double series of tubercles running 

 from the periphery of the mouth to the apex of the disc, but 

 there exists in addition on each side an outer series of smaller 

 tubercles which does not reach the summit. Along the middle 

 line of the ambulacra there also exists a double but indistinct 

 series on account of the small space left by the principal series. 

 The surface of the whole body, not occupied by the tubercles in 

 series, is covered with still smaller tubercles, which extend even 

 to the sexual and eye plates. The madreporic body is large 

 and heart-shaped. The mouth is proportionally large and cir- 

 cular, slightly notched. The auricles are rather thin ; their 

 pillars are oblique and united at their summit, where a notch 

 exists at the point of union. A sharp and low ridge runs from 

 one auricle to the other, thus connecting these parts at their 

 base. The spines are long, cylindrical, slender, very acute at 

 their extremity and longitudinally striated or furrowed. The 

 longest ones measure about an inch. From Cape Palmas, West- 



