8o 



mapliriulitcs. If these males were about to become extinct, the conti-ary might l)e expected to be tiie case. 4) The structure of 

 the dwarf-males indicates, in one way or other, a relationship to the hermaphrodites. If the dwarf-males are more primitive than 

 the hcrmaphro lites, I cannot account for the pesence of oviducts. As above mentioned, I conclude that these oviducts must 

 really be, either, remnants of hermaphroditism, or, the first development of female organs (in a young stage); the dwarf-males are, 

 consequently, onl\- \-oung heniiaplirodites. I think it is, indeed, most proLiable that some hernia])hnxlites, at all events in 

 their A^outh, perform, e.xclusivel)', a male function. Finally, if it is the case as Beard supposes, that the dwarf-males are 

 primordial and the diecious state the primary one, then the hermaphrodites must have been developed from males, and not 

 from females as Beard supposes. I think, in fact, that the \iew of hermaphroditism being, in all cases, the primitive state is 

 not so im.imilable as hitherto supposed. It cannot Vw denied that, in many cases, there is some support for the \-iew, that ni 

 parasitic life there is a tendency to produce hermaphroditism, as Yves Delage in his Report on the -Evolution de la .Saccu- 

 Iine« has stated. In the Myzostomidae, however, there is nothing found in support of the probability of that view. If, 

 however, it can be assumed that hermaphroditism ma>' be developed from gonochorism, then, gonochorism may again also, be 

 developed from hermaphroditism; there must, in both cases, exist a latent capability to torm the other state, and 

 I think, indeed, that both states have been present m the most primary stage, and have kept pace with each other, up- 

 wards, in the animal series. That hermaphroditism is, principally, produced by parasitism can not be assumed, because 

 there are a great many hermaphrodites which are not parasites, e. g. Oligochaeta, Polj'gordidae, Tardigrada etc. whilst, 

 on the other hand, there arc many parasites which are not hermaphrodites e. g. Myzostomida Cysticola, Histriodrilus etc., it 

 may, also, be said that Cymothoidae are, to a certain extent, diecious; at all events they are not true hermaphrodites. The 

 question of the origin of the hermaphroditism and gonochorism is b\- no means exhausted, and we have not heard the 

 last of it. 



Systematic position. 



I cannot agree with Beard in regarding the Myzostomida as belonging to the Chaetopods; there are too man_\- dis- 

 similar features in their structure, and I do not think that their development, as described by Beard, is quite that of a Chae- 

 topod.<. The absence of a praeoral ring of cilia, the relatively small development of the praeoral lobe, and the great 

 development of the bod\'-part of the lar\'a are no insignificant differences; they show that the larva is not a little differ- 

 entiated. The presence of a praeanal ring of cilia is common to most Annelid-larvae, and larvae of Mollusca, Bryozoa 

 etc. also posess such a ring, usually. In the absence of this ring, as well as in the rudimentar\' development of the praeoral 

 lobe, the larvae cf Myzostomida resemble those of Sipunculus; in their general structure there is, however, but little resemblance 

 to be traced. I am inclined to regard the Myzostomida as a peculiar, distinct, group belonging to the Annelids; related to the 

 Chaetopods but, also, showing a tendency towards some of the Arachnids (Linguatulida, Tardigrada and perhaps Pycnogonida) 

 and Crustaceans; the)' are sprung from the Trochophora; among the Archiannelids, their progenitor has been, chiefly, related to 

 that of Histriodrilus; on the other hand, it has, also, been related to that of the Arthropods, because the Myzostomidae show, 

 really, in their structure, a tendency towards these. They are, therefore, one of those groups presenting the greatest interest 

 as a subject for phylogenetic studies. 



