94 



ECHINOIDEA. II. 



specimen really came from that locality. Further, since the type specimen of Wyv. Thomson was 

 taken at 81.45 (3834'N. 72io'W. 1240 fathoms) 1 , and only two specimens are mentioned in the 

 Challengers-Report, one of which (St. 191) is no true A. rostrata, it seems not hazardous to suggest 

 that Bay of Biscay and Coast of Portugal* was wrongly named among the localities of A. rostrata. 

 Both the localities named in the Challengers-Report, p. 194, are thus wrong; on p. 220 the locality 

 Davis Strait is rightly named. 



A few remarks must be made on the pacific species, Acropsis fulva (A. Ag.) The structure of 

 the test has been very elaborately worked out by Professor Agassiz (Pan. Deep-Sea Ech. p. 194 97, 

 PI. 61,62), and the spines and pedicellarise have been described and figured by de Meijere (*Siboga- 

 Ech. p. 195. Taf. XXIII. Fig. 481 87). Having examined some specimens from Albatross& 81.3361 and 

 3399 in the U. S. National Museum I am able to give a little additional information. In the shape 

 of the tridentate pedicellarise I do not find any distinct difference from A. rostrata; I have seen none 

 with meshwork in the blade. The rostrate pedicellariae (only one specimen found) differ distinctly from 

 those of A. rostrata (PI. XV. Fig. 34); the blade is shorter and broader than in that species and some- 

 what serrate at the lower end. -- In the elongate specimen from the Challenger St. 191 I find the 

 tridentate pedicellariae somewhat different (PL XV. Figs. 6, 12, 27). In the larger ones the edges in 

 the lower part of the blade are very irregular, somewhat thickened or thorny, and there may be a 

 rather well developed meshwork. The smaller ones have upon the whole shorter and broader 

 valves than is the case in A. fulva and rostrata, and there is often some meshwork developed already 

 (PL XV. Fig. 27, comp. with Fig. 29). These small differences, in addition to those- pointed out by Pro- 

 fessor Agassiz (Pan. Deep-Sea Ech. p. 194), may perhaps tend to show that this specimen from the 

 Arafura Sea represents a third species, different from A. fulva, though certainly nearer related to that 

 species than to A. rostrata. Unfortunately the figures of pedicellariae given by Dr. de Meijere are so 

 little detailed that it cannot with any certainty be concluded from them whether his specimens agree 

 in regard to the pedicellaria? with A. fulva or with the Challenger-specimen from the Arafura Sea- 

 This question about a third species of Acropsis must be left ,undecided for the present; but the main 

 thing here was to show that the elongated form from the Arafura Sea is not A. rostrata, and this, I 

 think, has been put beyond doubt. 



Also on Aceste bcllidifcra a few remarks must be made here. (I have examined a specimen 

 from the Challenger St. 8 in the British Museum, and another from the Albatross* 81.2117, which 

 Professor Rath bun most liberally lent me for examination). First as regards the name Aceste, though 

 apparently so original, it is perhaps a little doubtful if it can be maintained, the name Acesta having 

 been used already in 1855 by Adams for a bivalve mollusc (Lima cxcavata). Still the ending of these 

 two names is really different so that I do not think it necessary to alter the name Aceste. (It might, 

 otherwise, easily be done sufficiently e. g. by adding only an s >, so that the name would be easily 

 recognizable). -- Regarding the structure of the test I have nothing to add to the careful analysis 

 given thereof by Loven; especially the apical system is seen by Loven's Figure (Pourtalesia. PL XX. 

 237) to differ considerably from what is seen in the Fig. 7. PL XXXIII. a. of the ^Challenger? Report. 



The pedicellarise have partly been figured by Professor Agassiz, but not all sufficiently de- 



' The Atlantic*. I. p. 381. 



