damage ensuing-. I onh' ventured slight attempts at construction, not being able to calculate 

 how the details — e. g. legs of males and larvae — would appear, if drawn in a position^ 

 dili'ering from the one in which they were found. As a lule I have figured the animals 

 with all the irregularities they presented, and the limbs in the position they happened to 

 occupy at the time of drawing. Where I had several specimens at my disposal, of coiu'se 

 I chose the one which was most suitable for illustrat on. 



I must briefly mention one point in my nomenclature. In 1S93 I stated (in »Zool. 

 Auzeiger«) that the two pairs of limbs which had been formerly named the first and second 

 pairs of maxillipeds, ought to be regarded as the second pair of maxillae and a pair of 

 maxillipeds. Shortly afterwards Dr. W. Giesbrecht gave very detailed proofs of the same 

 fact (Mitth. Zool. Stat. Neapel, 11. B.). I also proposed to introduce the names »maxillulae« 

 and >> maxillae* (in analogy with the commonly used names >'antennuhe« and antennae- <) for 

 the two pairs of jaws , and I shall here avail myself of these short , ' convenient and very 

 intelligible names. 



In conclnsion a few remarks may be offered about the plan of the present work. 

 For several reasons I have contented myself wth representing the external structure of the 

 adult animals and their post-embryonic development, and I have spent an exceedingly long 

 time, partly in finding females and eggs, males, larvae and pupae, partly in studying the 

 material I had discovered. The result is that at present scarcely any moderately large 

 family of genuinely parasitic Copepoda is so well known as the Choniostomatida?. I have 

 found the males of thirty-two of the forty-three species, the larvae of twenty-three, the pupae 

 or other stages of the post-larval development of a pretty considerable number of species. 

 At the same time I must call attention to the great and numerous gaps in the knowledge 

 of the metamorphosis of these animals, which vary remarkably according to the ditferent 

 species. On their embryology I do not enter at all, and their anatomy is almost totally 

 omitted; I could not have given information of any value unless I had stayed long enough 

 at the seaside to enable me to collect a large supply of living animals of several species, 

 but this would have considerably delayed and increased the work, wliich is rather voluminous 

 as it is ; so, not being able to present an exhaustive study of these topics, I have — contrary 

 to the habit of numerous authors — only treated what was indispensable to classification 

 (the genital region and receptacula seniinis). Besides, I should advise students not to enter 

 upon the anatomy of forms so small, difficult and for the most part rare, before having 

 acquired a thorough autoptical knowledge of representatives of various other families among 

 parasitic Copepoda. 



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