302 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



The specimens from Amboina are of special interest because they leave no 

 doubt as to what species of Diadema Rumphius (1705) called Echinometra petosa. 

 His specimens were the common Diadema of Amboiua, aud there can be no ques- 

 tion that the specimens brought by Mr. Barbour from the same place are the 

 same species. These ten specimens all agree in having the straight, slender pedi- 

 cellariae, which Mortensen (1904, Dan. Exp. Siara : Ech., p. 11) has pointed out 

 as characteristic of the commonest Indo-Pacific species of Diadema. Dr. Mor- 

 tensen follows Loven (1887, Ech. des. by Linn., p. 124) in attaching Linne's name 

 saxatilis to this species, but Loveu's argument seems very weak. It is only by 

 altering Linne's description and entirely ignoring his references to figures and to 

 geographical distribution that his saxatilis can be applied to any Diadema, and 

 even if all that were done, it would be absolutely impossible to tell to which of 

 the five species recognized by Mortensen, Linne's name should rightly belong. 

 On the other hand, Leske's figures, combined with Rumphius's good description, 

 leave no doubt that a Diadema is the basis of the name setosa, and since the type- 

 locality is definitely stated to be Amboina, examination of specimens from that 

 place is bound to show to what particular Diadema the name should be attached. 

 Of course it is quite possible that two or more species may occur at Amboina, 

 but there is no evidence that such is the case, and even if it should prove to be 

 so, the common species is evidently the one which Rumphius describes. It seems, 

 therefore, beyond doubt that Diadema saxatile Mortensen, 1904, is the true 

 Diadema setosum ; whether Loven's (18S7) saxatile is the same appears to be 

 indeterminable, while saxatilis Linue is almost certainly not a Diadema at all. 



The young Diadema from Japan, in the Owston collection, is a very remarkable 

 looking specimen, and I shall not be surprised if it proves to belong to an unde- 

 scribed species. It differs from all other young Diademas which I have ever seen, 

 or of which I can find records, in coloration. Instead of the usual black (or 

 brown) and white (or whitish) cross-banded primaries, this specimen has the 

 large spines light green with three or four cross-bands of purple. Unfortunately 

 no large tridentate pedicellariae are to be found, although the specimen is per- 

 fectly preserved ; presumably none have been developed. There are only eight or 

 nine coronal plates in each column, and the number of primary spines in the 

 ambulacra does not exceed ten in each vertical series. Consequently primary 

 spines are not numerous, and secondaries and miliaries are also noticeably few. 

 The longest spines do not exceed 20 mm. — In view of the fact that only a single 

 specimen of this handsome young Echinoid is available, it seems best to record it 

 under the name of the Diadema which is most likely to occur in Sagami Ray, 

 although none is as yet known from there. 



Echinothrix calamaris. 



Echinus calamaris Pallas, 1774. Spic. Zool., 1, fasc. 10, p. 31. 

 Echinothrix calamaris A. Agassiz, 1872. Pev. Ech., pt. 1, p. 119. 



2 specimens, 33-57 mm. in diameter. Amboina. Barbour collection. 



