K(l. VI: 8) THE CRINOIUEA. 7 



limit for the presence of the genital organs; they are just gradually diminishing in 

 size towards the 12th — 14th joint, and may continue as rudiments beyond that point. 



The eggs must break through the wall separating the ovarj- from the marsupium. 

 Whether a definite opening exists, I cannot ascertain definite!}-. The figure PI. IV, 3 

 would seem to prove that such a preformed opening does exist; but I have seen it 

 only in this one case. The eggs are not verj- large, only ca. 0.2-3 mm. Quite a 

 number of ripe or nearly ripe eggs are found at the same time in the ovary (PI- IV, 

 Figs. 2 — 4); but there is generally only one or two embryos in each marsupium, 

 rarely three (PI. Ill, Fig. 2). These facts would seem to indicate that some of the 

 eggs do not develop, but are dissolved and possibly serve as nourishment for the 

 embryos. I have in some cases found a yellow, coarsely granulated substance in 

 marsupia, without embr>'os, which had decidedly the appearance of being eggs in 

 disintegration. Tliis would also seem to corroborate the supposition that some of 

 the eggs are destined to serve as nourishment for the developing embrj'os. But 

 I cannot ascertain this as a definitely established fact. 



The embryos are found to be all at very nearly the same stage of development; 

 this would seem to indicate that the eggs are emptied into the marsupia not at any 

 time, but a larger number at the same time, as is also the case in other Crinoids 

 with free eggs, thus far observed. On account of this fact it was impossible to study 

 the whole of the embryonal development, only two stages being represented. Also 

 the postembryonal development remains unknown, no Pentacrinoids having been found. 

 It may be allowed to suggest that the Pentacrinoids remain attached to the genital 

 pinnules, as is the case in Tliauntatouictra iiutrix (see below, p. 17). P"or this sug- 

 gestion is speaking the fact that the embrj'os have no trace of vibratile bands and 

 thus must be incapable of swimming. But in the absence of any observations re- 

 garding the later stages of development, this can be nothing but a mere suggestion. 



An account of the structure of the embryos will be given in the memoir on 

 Crinoid development mentioned in the Introduction. It should only be mentioned 

 here that they are considerably larger than the embryos of any other Crinoid, as far 

 as known, being nearly 2 mm. in length. 



In PI. IV^ Fig. I is seen a small, elongate body lying in the cavity of the ovarj'. 

 This is a parasitic organism. Having been unable to find any other specimen of this 

 parasite, I do not venture to state definitely, what it is. It is nearest to suggest that 

 it is a Myzostomid — but this cannot be ascertained. In any case, it seems well 

 worth while pointing out the existence of a true internal parasite in this Crinoid. 



It is easily enough seen that this highly interesting Crinoid represents a new 

 genus. More difficult is the question about the affinities of that genus. 



Some of its structural features, evidently, are of a primitive character, e. g. the 



