CO ECHINOIDEA. I. 



fio-ured on PI. XLII. Fig. 8, which in the explanation of the figures is called a < globular-headed, 

 short-stemmed pedicellaria» of^. Grubci, is easih- recognizable; but does it really belong to^J. GrubcP. 

 I have not been able to find such pedicellarije, neither in xl. Grubei nor in the other allied species. 

 But it is strikingly similar to the peculiar short-headed pedicellaria of P/i. liiculciituui figured by 

 Agassiz (PI. X. a. Fig. 7, and PI. XLIV. Figs. 25— 26), and I must suppose a confounding to have 

 taken place. 



The third, smallest form of tridentate pedicellarise (PI. XIV. Fig. 10) is more simple, but also 

 highly characteristic. The blade is simple, but the apophysis continues into it as a high, sharp, 

 coarsely serrate keel; in the larger specimens of this form the keel reaches to the very point of the 

 blade, in the smaller generally only to the middle of the blade. On the sides of the keel there is a 

 rather coarse net of meshes which is, however, far from filling the blade; in the small specimens this 

 net of meshes is only slightly developed. The edge of the blade is finely serrate. When the pedicel- 

 laria is shut, the edges join through the whole length, only a quite small opening is found below. 

 This form has a rather long neck. The head 0-5 — i'"™. — In the triphyllous pedicellarise the cover- 

 plate is well developed, with a few holes; the edge of the blade is beautifully rounded and finely 

 serrate (PI. XII. Fig. 18). The stalks of the pedicellarise are of the common structure, only somewhat 

 stronger than is else the case in the Echinothurids. 



This group of species is very .sharply distinguished from all the other Echinothurids, and must 

 form a separate genus, which will, of course, get the old name of Asthcnosoma. The other species 

 referred to Asthenosotna do not justly belong to this genus, no more than the other species referred to 

 P/toriuosoma do in reality belong there. 



As mentioned above, Agassiz is inclined to think that ^J. Grubci is identical witli .i. variuiii. 

 Also de Loriol (246) advocates the same opinion. «La reunion de ces deux especes me parait fort 

 probable; cependant les exemplaires d'Amboine paraissent differer de ceux que M. Agassiz a fait 

 figurer, par leur forme circulaire, un arrangement des plaques un pen different dans les zones poriferes 

 et, aussi, par la structure de I'appareil apical qui, d'apres le dessin ne serait pas la meme (p. 367). To 

 this may be added the difference of the large pedicellarise pointed out alK)\'e. — As I have not had 

 both species for examination at the same time, and have moreover only seen a large specimen of A. 

 Grubci and a couple of small ones of A. variuiii^ I shall give no decided opinion of this question. 



In the work quoted above de Loriol further describes a >oimg Echinid which he calls 

 Astlunosoma variuntff - II me parait extremement probable que le petit exemplaire . . ., qui est un 

 jeune d'une espece de la famille des Echinothurides, pent etre envisage conune celui d' I'Asf/niiosoina 

 variuni Grube:>. It is scarcely an Fkhinothurid at all, far less a \oung one of A. variuvi. As appears 

 from the description and the figures, the arrangement of the pores (a single, regular series), the sjnnes, 

 the buccal membrane, the apical area are all so different from wluxt is else characteristic of the Echino- 

 thurids, lliat there can certainly be no question of its being referred there. P'or the present I sliall 

 express no conjecture as to where it may really have to be referred. 



End wig (257) is inclined to think that one of the specimens examined by him is a different 

 species from A. varium, especially because its large pedicellarise are different from those of A. variiun. 

 The figure given .shows, however, that it is only tlie second, broad form of tridentate pedicellarise that 



