REPORT ON THE ECHINOIDEA. 39 



Pliyllacanthus (Cidaris). 



Phyllacanthus, Brandt, 1835, Prod. Desc. An. 



PhyUacanthus annulifera. 



Cidarites annulifera, Lanik., 1816, Auim. sans Vert. 



PhyUacanthus annulifera, A. Agassiz, 1872, Revis. Ech., part 1, p. 150. 



Mr P. de Loriol [Mem. Soc. des. Sc. Nat. de Neufcliatel, vol. v. p. 23, pis. iii. to vi., 

 Mai 1873] has distinguished as Cidaris liltkeni a specimen closely alUed to Cidaris 

 anmdifera. The specimens collected by the Challenger of what I take to be (PhyUacan- 

 thus) Cidaris annulifera, show that the variation of the primary and secondary spines is 

 much greater than is admitted by De Loriol, after a comparison of the different spines of 

 the Challenger specimens with those of the Museum of Comparative Zoology I am 

 unable to distinguish Cidaris liltkeni from Cidaris anmdifera; De Loriol acknowledges 

 himself the identity of the structure of the test, and bases his principal characters on the 

 variation of the primary spines. They differ in the same specimen sufficiently to be 

 taken as belonging either to the typical Cidaris annulifera or to Cidaris liitkeni, and 

 even resemble sometimes so closely the spines of Stephanocidaris hispinosa as readily 

 to pass for spines belonging to that species. 



Station 186. September 8, 1874. Lat. 10° 30' S., long. 142' 18' E. ; 8 fathoms; 

 coral sand. 



Station 188. September 10, 1874. Lat. 9" 59' S., long. IZ9' 42' E. ; 28 fathoms; 

 mud. 



Cape York. 



Phyllacanthiui hactdosa. 



Cidarites hactdosa, Lamk., 1816, Anim. sans Vert. 



PhyUacanthus baculosa, A. Agassiz, 1872, Revis. Ech., part 1, p. 150. 



A specimen from Station 201 is extremely interesting, as it is the only specimen thus 

 far collected of this species in which all the primary spines belong to the type of Cidaris 

 proper, resembling to an extraordinary degree the elongated spines sometimes occurring 

 in specimens of Cidaris trihtdoides. The serrations of the shaft show no trace of the 

 lamellar arrangement forming a more or less prominent fluting of the tip of the spines 

 as in specimens of the typical Cidaris hactdosa; neither are there any prominent 

 serrations or spines on the shaft such as we find on forms usually considered as specific, 

 viz.: — Cidaris lima, Cidaris instillaris, or Cidaris krohnii, but which I have already 

 shown all belong to this species. The specimen figured in Revision of the Echini (pi. i.*", 



