1909. ] OF THE THIRD TANGANYIKA EXPEDITION. 49 
at Sumbu, western shore of the lake. From the same sample 
also several of the above described species of the genus Schizopera 
were derived. 
Tit. CYCLOPOIDA. 
The Cyclopoida found in the collection are referable to two 
particular sections of that extensive division, viz., the Gnatho- 
stomata and the Peecilostomata. The first of these sections com- 
prises the typical free-living Cyclopoida, in which the oral parts 
are normally developed. To the second section, on the other 
hand, are referred forms which lead a more or less parasitic life, 
and in which therefore the oral parts have been transformed in 
accordance therewith, though not to such an extent as in a third 
section, not represented in the collection, the Siphonostomata. 
Sect. Gnathostomata. 
Family CycLopipa. 
Genus Cyctors Miiller. 
By far the great majority of Copepod-species found in the 
collection belong to this extensive and widely distributed genus. 
No less than 20 different species have been determined, 16 of 
which have proved to be new to science. 
The distinction of the species of this genus is in some cases 
determined with no small difficulty. For, whereas some of them 
are at once recognised, there are other species which are so 
closely related, that a very careful examination is needed for 
distinguishing the one from the other. For the discrimination 
of nearly allied species, much stress has generally been laid on 
the structure of the rudimentary last pair of legs. The exami- 
nation of these diminutive appendages is, however, by no means 
easy, and cannot be effected without a very careful dissection of the 
specimens. There are several other characters, which are much 
more easily accessible for examination and consequently of more 
practical value. Among them may be mentioned the mutual 
relation in length of the caudal sete. As this relation has proved 
to be perfectly constant in all individuals of the same species, and 
admits of being examined at once, without any dissection of the 
specimens, it affords one of the practically best characters for the 
distinction of nearly-related species. Especially is the mutual 
relation between the innermost and outermost apical seta in 
many cases very characteristic, 
Owing to the great number of species comprised within this 
genus, it will probably in future be found advisable to effect a 
subdivision of it into several nearly allied genera. It is well 
known indeed that Dr. Schmeil, in his excellent account of the 
fresh-water Cyclopide, has arranged the European species in 
several groups, and in recent times some attempts have been made 
Proc. Zoo. Soc.—1909, No. LV. 4 
