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XII. Notes on some new or little-known Species of Freshwater Entomostraca. 
By JOHN LUBBOCK, Esq., F.R.S., F.L.S., Se. 
(Plate XXXI.) 
Read June 18th, 1863. 
CYCLOPID~. 
CYCLOPS. 
AT the time when Dr. Baird published his excellent work on the British Entomostraca*, 
although many species of Cyclops had been described, principally by Koch, yet the 
characters used by that author were not those upon which new species could in that 
group be properly established, and accordingly Dr. Baird exercised a wise discretion in 
uniting them under a single head. Since the appearance of his work, Continental 
naturalists have carefully studied the genus, and have ascertained certain differences 
which may be satisfactorily used as specific characters, and which, as I have already 
observed in the ‘ Transactions’ of this Society (vol. xxiii. p. 176), are found principally 
in those organs which exhibit secondary sexual differences. 
Considering that they are among the commonest inhabitants of our fresh waters, that 
probably there is not a weedy pond in the country which does not contain two or three 
species, it is somewhat remarkable that the genus should have been so completely 
neglected by our English zoologists; and yet I am not aware that any one has written 
on the Freshwater Cyclopide of Great Britain since the appearance of Dr. Baird’s work, 
or has attempted to compare our English forms with those described by the foreign 
carcinologists, and especially by Claus and Fischer. 
1 have now to record seven species which occur in our Kentish ponds; six of which, 
namely, C. serrulatus, C. coronatus, C. tenuicornis, C. brevicaudatus, C. canthocarpoides, 
and C. brevicornis, have been met with on the Continent; but the seventh appears to be 
new, and I have much pleasure in dedicating it to Professor Claus, who has contributed 
50 much to our knowledge of the genus. 
CYCLOPS SERRULATUS, Fischer, Bull. de la Soc. des Nat. de Moscou, 1851-52. 
In this species the antennze have only twelve segments. 
Female. The figures given by Fischer and Claus of the anterior antennæ are not alto- 
gether correct. The hairs are not, as might be inferred from the figure given by Claus, 
inserted on both sides of the antenna, but, as usual, are, with the exception of the three 
apical segments, confined to the anterior side. The hairs on the basal segments are in 
the figures neither sufficiently numerous nor unequal. For instance, the basal segment 
has at least eight hairs of different lengths, the one at the apex being the longest. Again, 
* «Natural History of the British Entomostraca,’ by W. Baird. Printed for the Ray Society, 1840. 
VOL. XXIV. 2D 
