BRANCHlOPpDA. 119 



In the remaining Lophyropa of our firsttdivision, the thorax, as 

 in the Condylura, is divided into several segments, the first of which 

 is much the largest^ they have but one eye situated in the centre of 

 the front between the superior antennae. Such is the 



Cyclops, Mull., 



So well studied by Jurine, Sen., and Randohr. The body is more 

 or less oval, soft or gelatinous, and divided into two portions, one 

 anterior, composed of the head and thorax, the other posterior, or 

 the tail. The segment immediately preceding the sexual organs, 

 and which, in the female, is provided with two appendages in the 

 form of little {eet—ftdcra^ Jurine — may be considered as the first 

 of the tail, which is not always decidedly or suddenly distinguished 

 from the thorax. It is composed of six parts or segments; under the 

 second in the males, are two articulated appendages, sometimes sim- 

 ple, and at others with a small branch on the inner side of various 

 forms, and constituting, either wholly or partially, the organs of gene- 

 ration. The vulva, in the other sex, is situated on the same segment. 

 The last one is terminated by two points or stylets, forming a fork, 

 and is more or less furnished with setae or penniform threads. The 

 other or anterior portion of the body is divided into four segments, 

 the first of which is much the largest, and composes the head and 

 part of the thorax, which are also covered by a common scale. In 

 it, are inserted the eye, four antennae, two mandibles — mandibules 

 internes of Jurine, furnished with a palpus, either simple or di- 

 vided into two articulated branches, two jaws— 'mandibules externes, 

 or levre avec des barbillons of Jurine(l), and four feet, each di- 

 vided into four cylindrical stems furnished with hairs or bearded 

 threads; the anterior pair, corresponding to the second jaws, differs 

 slightly from those that follow. Jurine compares it to a kind of 



The genus Pontia, Id., lb., XIV, appears to us to approach Cyclops. The 

 head is distinct from the trunk, and terminated by a rostrum which is rather acute 

 and appears to be formed of two pieces; it has two sessile eyes; four antennse, the 

 superior of which are setaceous, multi-articulated and ciliated; the inferior are 

 pediform, composed of a peduncle, serving as a base to two divisions or branches, 

 each terminated by a pencil of hairs, one of them having two joints, the last 

 widened at the end, and the other consisting of one. The thorax is divided into 

 five annuli, and has six pairs of natatory and bifid feet. The abdomen is formed 

 of two segments and terminated by two spatula-like appendages or fins, 



(1) According to the successive order of the parts of the mouth in the Deca- 

 poda, the part situated immediately beneath the mandibles is the ligula; but the 

 dentation of those here spoken of indicates maxillary organs. The ligula may 

 have escaped the notice of M. Jurine. 



