75 



the band rising over it -- in the preserved specimens at least. The suboral 

 cavity is very distinct. The body is short, obliquely truncated as in Ech. 

 lucunter. The postoral arms are somewhat unusually long. On the sides 

 of the body the ciliated band reaches Fur backwards. The pigmentation 

 is not very conspicuous; there is an indication of pigment spots in the 

 point of the arms and scattered red pigment cells over the body. 



Xo figures can be given of the skeleton on account of its having been al- 

 most dissolved in the preserved specimens; but I have noticed that tin- 

 body skeleton forms a complicate basket structure, the recurrent rod 

 being double; it is not very thorny. The postoral rods are fenestrated. 



As seen in PI. XII. Fig. 2 there are still traces oF the skeleton preserved, 

 showing the double recurrent rod, but it is insufficient for giving detail 

 figures. The postoral rods have been restored in the figure, but it is 

 distinctly seen in the specimen thai they are fenestrated and also that they 

 are somewhat thorny. 



Echinometra Mathaei (BI\.). 



Fertilization of this species was undertaken repeatedly in April 1915. 

 but never very successfully, only once the young Pluteus-stage being 

 obtained. Moreover, the skeleton has been completely dissolved in the 

 specimens preserved; no more information can therefore be given than what 

 is found in my notebook, namely that the body skeleton forms a basket 

 structure, very thorny, and very oblique, the recurrent rod being consider- 

 ably shorter than the body rod. - rnforlunalely it is not slated in my 

 book, whether the recurrent rod is double as in E. obloiu/a and lucunter. 

 The postoral rods are Fenestrated. The larva is rather much pigmented, 

 almost opaque. 



In view of the fact that de Meijere 1 ) and H. Ly m. (Hark-) are inclined 

 to regard Ech. oblongu only as an extreme form of Ech. Malhtfi, while 

 Doderlein 3 ) makes it the lype oF a separate genus (on account of its 

 peculiar triradiate spicules), it is interesting to notice thai there appears 

 to be quite a conspicuous difference between the larva. 1 of the two forms, 

 which is decidedly in favour of their being, at least, distinct species. Kven 

 in the first cleavage processes I noticed a marked difference between them, 

 the cleavage cells lying much more closely pressed against one another 

 in E. oblomja than in Mnthivi (while the eggs did not appear to lie different 

 in size or color). On account of the incompleteness of this record of 



' Siboga-Echinoidea 1004, p. 101. 



-) Hawaiian a. other Pacilir Echini. The I'cdiimhi- .... and Kchinometrida-. Mem. 

 Mus. Comp. Zool. XXXIV. 1912, p. 370. 



3 ) Echinoidea d. deutschen Tiefsee-Expedilion. p. 21>:i. 



10* 



