208 imiTisn I:\TOMOSTRACA. 



to a female, and have never seen an adult without it, as 

 the female has it constantly attached, though the young 

 in the ova are ready to be hatched. It is so hard and 

 horny too, and differs so much in texture and appearance 

 from the spermatic tubes found in Diaptomus, being too 

 solid to contain any soft matter, or to form a hollow tube, 

 that I am much inclined to doubt the accuracy of Siebold's 

 conjecture, and to believe that the true use of these organs 

 is still unknown. 



In copulation, the male of this species lays hold of the 

 terminating segment of the abdomen of the female, just 

 above the commencement of the long filaments which 

 issue from it. 



Hal. Ponds and ditches of fresh water, all the year 

 round; common. 



2. CANTHOCAMPTUS STROMII. Tab. XXVII, fig. 3, 3 a. 



CYCLOPS STROMII, 7_>v;,v/, Mag.Zool.and Bot., i,330,t. 9, f. 23-25, 1837. 

 CYCLOPS BREVICORNIS, J'xiiril, Trans. Bunv. Xat. Club, i, 97, 1835. 

 CANTHOCARPUS STROMII, Buird, Trans. BCT\Y. Nat. Club, ii, 15 I, 1 s I ."> . 



NAI 1'i.irs STKOMII, /'/////'/-///, \\ ic^iu. and Erichs. Arckiv, 1 sl,'5, p. (\\\. 



The thorax and abdomen consist of ten segments, 

 gradually tapering to the extremity, without any decided 

 difference between them. The first segment, consolidated 

 with the head, is the largest, and is furnished with a 

 conical beak ; the last segment terminates in two lobes, 

 which give issue to tAvo setae. These are much shorter 

 than those of the preceding species, being scarcely half 

 the length of the body. 



The antennae are composed of eight short articulations, 

 and at the junction of the fifth with the sixth they have 

 a lateral joint. In the male, the swelling and hinge-joint 

 arc as in the preceding species. Each of the articulations 

 of the antenna' throws forward one or two short seta'. 

 The anteunules are formed of two articulations, the 

 >eeoii(| heing terminated by about four somewhat long 

 filaments. The mandibles were not seen. The posterior 



