Mr H, Goodsir on the S^xes of the Cirnpeds, Sfc, 339 



of a peduncle, consisting of two joints, two quadrate scales arising from 

 the extremity of the distal ; long spines which are fringed on either sido 

 arise from the extremities of each of these. The third pair of foot-jaw$ 

 are very similar in their appearance to those of Cetochilus. Each pf them 

 consists of a large flattened scale-looking body, having a number of pro- 

 jections from its extremity and from either side ; each of these projec- 

 tions are armed with long and thickly fringed setso. The fourth foot- 

 jaw consists also of one piece only which is convex on its outer edge, 

 and concave on its inner, which is armed with very long fringed setae. 



The fifth is small and composed of two divisions, the internal of which 

 consists of one joint only ; the external is six-jointed ; each of these are 

 armed with spines on the inner edge. 



The true ambulatory legs are ten in number, there being five pairs. 

 These legs are all similar in their structure to one another. They con- 

 sist of two divisions, arising from a common pedicle, which consists of 

 two segments. The external division is composed of four segments, the 

 last of which is ovoid, and is serrated on each side, from each of which 

 serrations there arises a strong spine of moderate length, those from the 

 external edge being shortest ; the internal division consists of two seg- 

 ments which are also spined; all of these have more of the characters of 

 spines than setae, and are totally free of any fringe. 



The abdomen is five-jointed, the last segment bearing two oblong 

 quadrate scales from the extremities of each of which arise five long and 

 very thickly fringed setee. 



PLATE IV * 



Fig. 1. One of the third pair of foot jaws of IrensBUS splendidus. 

 ... 2. Tabular portion of eye of same, 

 ... 3. Left antennas. 

 ... 4, Right antennae. 

 . . » 5. Fourth pair of foot-jaws. 

 ... 6. Fifth pair of foot-jaws. 

 ... 7. Second pair of foot-jaws. 

 ... 8. Caudal segment. 

 ... 0. External organs of generation of male. 



PLATE VL 



Fig. 1 . Side view of Cetochilus septeutripnalis. 

 ... 2. Porsal view of same. 

 ... 3. First or anterior 'pair of antennae. 

 ... 4, Second do, 

 ... 6. Second pair of foot jaws, 

 ... 6. First do. 



... 7. Third do. 



... 8. Tail or caudal segment. 

 ... 9. Fourth pair of foot-jaws, 

 ... 10. Fifth pair of do. 

 ...11. Second pair of ambulatory legs. 



... 12. One of the first pair of foot-jaws of Ireneeus splendidu5. 

 ...13. Irenajus splendidus, 

 . . . 14. Natural size do. 

 ... 15. Dorsal view do. 

 ... 16, One of the second pair of foot-jaws. 



* Description of Plate IV. continued from p. 104. 



