ECHINOIDEA. I. 



figured on PI. XLJI. Fig. 8, which in the explanation of the figures is called a globular-headed, 

 short-stemmed pedicellaria > oiA. Gmbet, is easily recognizable; but does it really belong to A. Grubcrt 

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

 But it is strikingly similar to the peculiar short-headed pedicellaria of Ph. luculentum figured by 

 Agassiz (PI. X. a. Fig. 7, and PI. XLJV. 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 mm . - - 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 (PL 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 coiirse, get the old name of Asthcnosoma. The other species 

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

 Phormosoma do in reality belong there. 



As mentioned above, Agassiz is inclined to think that A, Grubei is identical with A. varium. 

 Also de L/oriol (246) advocates the same opinion. L,a 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 peu different dans les zones poriferes 

 et, aussi, par la structure de 1'appareil apical qui, d'apres le dessin ne serait pas la meme (p. 367). To 

 this may be added the difference of the large pedicellariae pointed out above. As I have not had 

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

 Grubei and a couple of small ones of A. varium, I shall give no decided opinion of this question. 



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

 Asthenosoma varium?? - - I1 me parait extremement probable que le petit exemplaire . . ., qui est un 

 jeune d'une espece de la famille des Echinothurides, peut etre envisage comme celui d' I' Asthcnosoma 

 varium Grube. It is scarcely an Echinothurid at all, far less a young one of A. varium. As appears 

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

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

 thurids, that there can certainly be no question of its being referred there. For the present I shall 

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



L,udwig (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. varium. 

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



