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iiiostomatidse. The dift'ereiices between the families will be shown most clearly by giving a 

 short description of each. In the Choniostomatidae both sexes possess at had antennnlas, a 

 month with mandibles, maxilliilae and niaxillse, and the males have always maxillipeds, and 

 they fix their spermatophores on the females in a normal way. The female deposits its eggs 

 in one or two free lumps or, in most cases, in ovisacs, of wliich at least four or five and 

 sometimes more than twenty are found; the larvae attach themselves by an adhesive plate 

 on the forehead and — whether passing through the pupa stage or not — develop them- 

 selves into animals of eithei- sex. In Herpyllobiidse both sexes lack antenuai, mouth and 

 appendages; the females project a mysterious body or two ramified tubes into the host 

 and draw nourishment through these organs. The males project from the anterior part of 

 their body in advance of the mouth of the larval skin two long spermatic ducts, which are 

 formed by a secretion in the genital organs, and through these canals nearly the whole sub- 

 stance of the body , having been transformed in the service of propagation , is transferred 

 into the female. The female has \\\(y ovisacs; the larva attaches itself by a gluey sub- 

 stance proceeding from the mouth, and is transformed into a limbless male or female. In 

 the latter case the animal forms a stalk which pierces the skin of the host, inside which 

 it dilates and develops into the above-mentioned organ of nutrition. — Whereas the Cho- 

 niostomatidae, on the whole, fit in well among the other families of parasitic Copepoda, the 

 Herpyllobiidae remove themselves from the others by a series of very peculiar features, 

 occupying a more isolated position than any other of the families. 



This, I hope, will be sufficient to prove that the juxtaposition by the authors of 

 the two families in question as sub-divisions of one family, is contrary to all sound classi- 

 fication. I think also that sufficient light is thrown on the characters and hypotheses of 

 the authors. The present work being a kind of monograph, I found it necessary to write 

 tins rather detailed critique of their publication. However, this task has not been at all 

 pleasant to me, because in another branch, the Epicaridea, they have published works 

 which must be considered the principal sources of our knowledge about important groups 

 belonging to tliis large and difficult family. In the interest of the authors and of carci- 

 nology, as well as for my own sake, I wish they had not published their four, at least not 

 the two last of their contributions (the preliminary note in 18ii3 and their final essay 

 1895) about Choniostomatidae. It Avould indeed have been very natural to postpone the 

 publication of their two last papers , as their material of these animals (whose manipulation 

 presents considerable technical difficulties) was rather scanty, and as, even as early as 1891, 

 they know that I was preparing a work based on very abundant material. (I need scarcely 

 add that the fact of their publishing a report about one species previously to myself atfects 

 me very little; indeed I might easily have secured this priority by some >preliminary note«). 

 If, nevertheless, they were intent upon describing their few animals, their researches might 

 and ought to have been much better, and they ought to have abstained from filling up i-eal 



