820 DR. W. A. CUNNINGTON ON PARASITIC 
a list of the African forms described for the first time in this 
paper :— 
LAKE TANGANYIKA. 
Lerneocera diceracephala. 
Lerneocera haplocephala. 
River NILe. 
Lerneocera haplocephala. 
Lerneocera temnocephala. 
For the purpose of illustration, I have made use of photo- 
micrographs taken from the actual specimens themselves. They 
are by no means easy objects to photograph, but in spite of 
imperfections, the figures will make clear the various external 
characters which have been used for the systematic descriptions. 
I have to thank Prof. Dendy, of King’s College, London, for - 
permission to do this photographic work in his laboratory.—The 
plan has been adopted of giving in each case a view of the head 
and cephalic arms from above. This was done by von Nordmann, 
one of the earliest writers on the genus, but his example has 
not been widely copied. It needs some trouble to support the 
specimens in the position necessary to secure such a view, but 
the figures obtained illustrate the nature of the head region 
far better than any others could do. 
2. Systematic Notes and Description of New Species. 
The literature which deals with the different species of the 
genus Lerncocera is somewhat scattered and not always easy to 
obtain. Although a list of the known species with synonyms is 
given by Bassett-Smith*, it is marked by material inaccuracies, 
so that it would seem worth while at this point to include a list 
which may be useful to future investigators as a starting point 
for their researches. No attempt has been made to give an 
exhaustive list of the authors by whom the species have been 
cited, as this would take up a good deal of space and serve no 
useful purpose. Only those works are referred to which have a 
bearing on the synonymy or which contain a record of original 
observations. 
List of described Species with Synonyms. 
|. LerN&OcERA CYPRINACEA T (Linneus) f. 
‘‘Lernea tentaculis quatuor: duobus apice lunulatis.” 
Linneus, Fauna Suecica, Ed, I. 1746, p. 367, tab. 11. 
Lernea cyprinacea Linneus, Systema Nature, Ed. X. 1758, 
p- 695. 
* Proc. Zool. Soc. 1899, p. 480. 
+ So far as I can ascertain, no one has ever fixed the type species or genotype of 
Lerneocera. Assuming this to be the case, in order to maintain the usage of all 
modern writers, I hereby select cyprinacea as genotype of Lerneocera. 
~ Parentheses enclosmg the Author-citation after specific names are used in 
accordance with Art. 23 of the International Rules of Nomenclature. 
