REPORT ON THE ECHINOIDEA. 43 



The primary interatabulacral radicles (PI. III. fig. 7) of this species are in the 

 specimens collected more uniform in shape than those of Porocidaris j^urj^urata . 

 They are often three times the diameter of the test, cylindrical, slightly tapering, finely 

 striated longitudinally, with minute sharp serrations. They diff'er from those of Poro- 

 cidaris purpurata in having a short collar above the milled ring, while in the primary 

 spines of Porocidaris purpurata the collar is frequently half the length of the spine and 

 of a dark colour, in striking contrast to the white shafts. On the actinal side round the 

 actinostome some of the primary interambulacral spines assume the curved spatula shape 

 with serrated edges so characteristic of the spines of this genus (PI. III. fig. 8a, h), the 

 actinal opening is small (PI. III. fig. 3), and the whole surface is covered by the long im- 

 bricating plates of the ambulacral system ; the nature of these plates as modified ambu- 

 lacral plates is readily traced in one of the specimens examined, where the ambulacral 

 plates of the test proper are still partly soldered to the coronal plates. The interambu- 

 lacral plates, however, appear independently as small plates, and are not ordinary in- 

 terambulacral plates modified, as is well shown by Loven (Etudes sur les Echinoidees) in 

 his drawing (woodcut, page 29). 



The pedicellarise characteristic of this species are figured on Plate III. figs. 10, 11, 12. 

 In Porocidaris elegans the large-headed short-stemmed pedicellarise, \ery similar to 

 those of Dorocidaris, vary greatly in shape (PI. XLIV. figs. 6, 7, 11), and the short- 

 stemmed globular abactinal pedicellariae (PI. XLIV. fig. 10) are somewhat pyramidal and 

 elongate. 



Station 214. February 10, 1875. Lat. 4° 33' N., long. 127° 6' E. ; 500 fathoms ; 

 bottom temperature, 5 '3° C. ; globigerina ooze. 



Station 164a. June 13, 1874. Lat. 34° 13' S., long. 151° 38' E. ; 410 fathoms; 

 grey ooze. 



Goniocidaris. 

 Gonioddaris, Des., 1846, in Agass. et Des., Cat. Eais. 



Goniocidaris canalicidata (Pis. II., XLIV. figs. 1-3). 



Temnoeidaris canaliadata, A, Agassiz, 1863, BuU. Mus. Comp. Zool., vol. i. 

 Goniocidaris canaliculata, A. Agassiz, 1872, Revis. Ech., part 1. 



In the Revision of the Echini, I referred Temnoeidaris canaliculata (A. Agassiz, Bull. 

 Mus. Comp. Zool., 1863, vol. i. p. 18) to Goniocidaris. The material then at my com- 

 mand was not very ample, and the specimens collected by the Challenger at Kerguelen 

 Island, in the Straits of Magellan, and at the Falkland Islands, have brought out some 

 interesting points, showing that the deep vertical sutural line (PI. II. fig. 4), on 

 account of which this species was removed to Goniocidaris, is frequently totally 

 obliterated (PI. II. fig. 5) by secondary granulation and by tubercles, both in the 



