Mr. Lubbock on new species of Entomostraca, 403 



at present known, however, it is separated by the arrangement 

 of the setse of the anterior antennae. 



It was frequent at Weymouth this last September and Octo- 

 ber, and in confinement preferred the top of the water, and the 

 sunny side of the glass in which it was kept. Several specimens 

 had spermatic tubes attached to them. 



Length ^jth of an inch. 



PL X. figs. 1-6. 



Calanus anglicus, n. s. 



Frons rotundata, contracta. Cophalothorax 4 -articulatus, postice 

 rotmidatus, superne visus sinuatus, subacutus. Antennae corpore 

 paulo breviores, setis brevibus, subapicalibus longioribus, postica 

 penultiraa brevi. Pedes primi, ramo uno 3-articulato, altero 1- 

 articulato. Pedes alii, ramis ambobus 3-articulatis. Abdomen 

 4-articulatum ; stylis setisque abdominalibus mediocribus. 



This species occupies a place in the genus close to C. IceviSy 

 with which alone it can be confounded. The anterior penulti- 

 mate seta of the anterior antenna is much longer than the pos- 

 terior penultimate, and the antennae themselves are rather shorter 

 than the body. Moreover, ail my specimens had the abdomen 

 four-jointed. It might be objected to this, that my specimens 

 may have been males, and those of Dr. Dana females ; but I 

 believe that I found both sexes, — at least some had the posterior 

 abdominal segment quite short, while in others it was nearly as 

 long as the preceding segment. One specimen had, attached 

 to the first abdominal segment, a sac, containing a round, darkish 

 body, which seemed too large to be an e^^ (PL X. fig. 10). 



Colour red. Length of cephalothorax -028 of an inch ; total 

 length -04. Length of anterior antenna (measured across the 

 curve) '035. 



Caught at Weymouth in October 1857. 



PL X. figs. 9 & 10. 



DiAPTOMUS. 



This genus, when originally founded by Mr. Westwood, con- 

 tained only our well-known freshwater species, D. Castor ; and 

 it maintained its freshwater character until I assigned to it, with 

 some doubt, the marine form D. dubius. I have now to describe 

 two new species, both characterized by having the eyes small 

 and close together, if not united; the right anterior antenna of 

 the male, and the fifth pair of legs in the same sex, prehensile; 

 and the maxillipeds and second pair of antennre Calanoid. Prof. 

 Dana describes the posterior legs of the female as being long, 

 thick, and unlike the preceding pairs. In these organs, how- 

 ever, there is considerable variation : in D, longicaudatusj now 



26* 



