3 
damage ensuing. I only 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 
differing from the one in which they were found. As a rule [ have figured the aninals 
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 course 
I chose the one which was most suitable for illustrat on. 
I must briefly mention one point in my nomenclature. In 1893 I stated (in » Zool. 
Anzeiger«) 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 maxille 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 »maxillule 
and »maxilla« (in analogy with the commonly used names »antennule« and »antenne«) for 
the two pairs of jaws, and [ shall here avail myself of these short, convenient and very 
intelligible names. 
In conclusion a few remarks may be offered about the plan of the present work. 
For several reasons I have contented myself with 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, larve and pupx, 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 Choniostomatide. I have 
found the males of thirty-two of the forty-three species, the larve of twenty-three, the pupe 
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 different 
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, which 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 seminis). 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. 
