Mr. Lubbock on new species of Entomostraca. 405 



I found some specimens agreeing with this species in the form 

 of the second pair of antenn?e, second pair of maxilHe, ccphalo- 

 thorax, the first and fourth pairs of legs, niaxilHpeds, and the 

 abdominal lamella. The fifth pair of legs, however, were large 

 and natatory, but the inner branch exactly agreed with that of 

 the male. The outer one was two-jointed, the apical segment 

 twice as large as the basal, and bearing at the free end a large 

 spine, and on the inner margin four long hairs, all on the apical 

 half of the segment. I believe therefore that these were females 

 of this species. 



I have named it after Mr. Spence Bate, who has done and is 

 doing so much good service in the cause of science. 



Caught at Weymouth, October 1857. 



Length of cephalothorax "034; of abdomen "016; of anterior 

 antenna '046. 



PI. XL figs. 1-3. 



Several specimens were attacked by one of the parasitic Iso- 

 pods, apparently an Anilocra, which was firmly fastened to the 

 back of its victim. This is the first time, I believe, that a 

 Crustacean parasite has been observed attached to any of the 

 Cyclopoidea. The Anilocra was more than half as long as the 

 DiaptumiLS. 



Diaptomus longicaudatus , n. s. 



Frous obtusa. Cephalothorax postice rotundatus. Antennae anticae 

 corpore breviores, setis brevibus, subeequis. Pedes primi, ramo 

 uuo 3-articulato, altero 2-articulato. Pedes postici, uuo tautuni 

 ramo prtediti. Abdomen 5-aiticuIatum ; styli caudales longi, 

 abdomiue vix breviores. 



The absence of angles to the cephalothorax, and the structure 

 of the fifth pair of legs, separate this from the preceding species ; 

 but as it has the right antennse and i-ight posterior leg of the 

 male prehensile, and the second pair of antennse Calanoid, it 

 must belong to this genus. 



The first pair of antenxue are shorter than the body, but longer 

 than the cephalothorax ; the seta3 are all short, none of them 

 much exceeding the length of one of the segments. 



The second pair of antenna are Calanoid. 



The maxillipeds closely resemble those of Diaptomus duhius. 



The first pair of legs have one segment three-, the other two- 

 jointed. This is also the case with the first pair. 



The fifth pair of legs are prehensile and Pontelloid. The 

 figure will give a better idea of their form than description can 

 convey. 



The abdomen is five-jointed. The caudal lamella is nearly as 

 long, and has five hairs at the end, of the usual relative lengths. 



