Rev. A. M. Norman on Acantholeberis, Lilljeborg. 409 



parts to be examined, and thereby suddenly destroying vitality 

 and coagulating the proper juices, renders the existence of vasa 

 propria in certain parts clearly demonstrable. 



XLIV. — On Acantholeberis {Lilljeborg), a Genus of Entomo- 



straca new to Great Britain. By the Rev. Alfred Merle 



Norman, M.A. 



[Plate XL] 



Fam. Daphniidse. 



Genus Acantholeberis (Lilljeborg). 



(Syn. Acanthocercus, Schodler.) 



Anterior antennae large and conspicuous, porrected from the 

 front of the head. The upper branch of the posterior antennae 

 four-jointed, and bearing at its termination three plumose setae 

 and a spine : lower branch three-jointed, and having the first 

 joint provided with a remarkably long-spined seta, the second 

 also furnished with one very long seta, and the last joint termi- 

 nating in three setae and a spine. The postero-ventral angle of 

 the carapace is fringed with very long setae of a spine-like cha- 

 racter. Feet five pairs. Intestinal canal simple and straight at 

 first, but furnished with a loop near the anus. 



The genus Acanthocercus was founded by Schodler, in the 

 \ Archiv fur Naturgeschichte ' for 1846, for the reception of a 

 remarkable Entomostracan which Muller had described in the 

 'Zoologia Danica,' under the name of Daphne curvirostris. 

 Fitzinger had, however, established a genus of reptiles under the 

 same name three years previously ; and Lilljeborg, therefore, in 

 his work on the Entomostraca (De Crustaceis ex ordinibus tribus 

 Cladocera, Ostracoda, et Copepoda in Scania occurrentibus) 

 changed the name of the genus to Acantholeberis. 



Ih general characters Acantholeberis is closely — perhaps almost 

 too closely — allied to Macrothrix (Baird). The resemblance is 

 seen in the general form of the carapace and of the organs of the 

 body, but especially in the large size and position of the anterior 

 antennae, and in the peculiar and exceptional structure of the 

 long seta of the first joint of the lower branch of the. posterior 

 antennae. The chief differences are to be found in the number 

 of setae on the upper branch of the posterior antennae, which in 

 Macrothrix are four, but in Acantholeberis only three ; and in 

 the fact that there is a loop in the intestinal canal of Acantho- 

 leberis towards the posterior extremity below the point of attach- 

 ment of the fifth feet ; while in Macrothrix there is no such fold, 

 the course of the canal being straight. 



In 1858, Lievin described a second species of the genus ; but 

 Ann.^ Mag. N. Hist. Ser.3. VoLxi. 27 



