J3 



part of the interambulacra light coloured and contrasting witli the dark colour of 

 the outer part of the area. The other specimens are uniformly coloured, though 

 in two of the specimens from St. 144 the median ]iart of the interambulacra is 

 somewhat lighter. Dr. Meijere does not think them to be two species, and, of 

 course, I dare not assert the contrary without having examined the specimens in 

 ([uestion. But I think the matter deserves a close examination based on large 

 material. — Sluitek (Op. cit. j). 290) mentions A. pnlvinata from Billiton and Krakalau; 

 in „Die Echiniden-Sammlung des Museums zu Amsterdam"') he refers these speci- 

 mens to A. radiata on account of the presumed inconstancy of the distinguishing 

 characters of A. radiata and piihnnata, which Agassiz thought he had proved. 

 According to de Meijere (Op. cit. p. 55) three specimens in the Museum of Amster- 

 dam named Astropyga radiata are really Chcetodiadema gramdatiim, and probably the 

 specimens from Billiton and Krakatau will prove to be the same species. That they 

 are not A. palvinata we may take to be certain. 



In the „Challenger'-specimens from Honolulu I found a worm-like animal 

 parasitic in the spines; it is found half buried in the point of the spine, which has 

 become a little swollen on that account. Prof. Shipley who has dissected two 

 of these specimens thinks they are a parasitic Mollusc; bul the material in hand 

 is not suflicient for giving a description of this curious parasite. 



4. Chaetodiadema granulatum Mrtsn. 



PI. I. Figs. 1, 3, 21—22. PI. III. Fig. 11. PI. IV. Figs. 1, 4, 13-1.5, 24, .32. PI. V. Figs. 10. 18, 19, 22, 35. 



AsfropiKja pnlvinata (pro parte). AciASSiz. 1881. Report ou the scientific Results of the voj'age of H. 

 M. S. „Challenger". III. Echinoidca. p. 70. 



— — (?) SnjrrEK. 1889. Die Evertebr. a. (I. Samnil. d. naturwiss. V'ereins Batavia. Eehinoidea. 



p. 290. 



— radiata (pro parte). Si,i rn;n, ISi).'). Die Echiniden Sammlung des Museums zu Amsterdam. 



Hijdr. tot de Dierkunde. All. 17. p. 68. 

 Chcetodiadema ijramilatnm. Th. Mortensen. 1903. Chætodiadema granulatum n. g., n. sp., a new Dia- 



dematid from the Gulf of Siam. Vidensk. Medd. Naturh. Foren. Kjobenhavn. 

 1903. p. 1. 

 — — DeMeijeme. 1904. Eehinoidea d. Siboga-Exped. p. .'>4. Taf. III. Fig. 28, Taf. XI. 



Fig. 101, Taf. XIV. Fig. 205-208. 



After the publication of my preliminary description of this interesting form 

 DE Meijere gave an additional description and some figures of the specimens 

 taken by the „Siboga --Expedition. As I have yet several tilings to add, it will be 

 desirable, however, that a complete description should be given here, as promised 

 in the preliminarj' description. 



The test is greatly depressed and very llexible as in the Echinothurids. Seen 

 from the abactinal side the animal looks much like Astropyga. The apical area 



') Bijdr. tot de Dierk. all. 17. 189.'>. p. 68. 



