52 REY. A. M. NORMAN, M.A., 
1V-—On Acantholeberis (Lilljeborg), a Genus of Entomostraca 
new to Great Britain.* By the Rev. Atrrep Merrie Norman, 
M.A. [ Plate I.] 
Fam. Daphniide. 
Genus AcanTHoLeBERis (Lilljeborg). _ 
(Syn. Acanthocercus, Schodler.) 
Anterior antenne large and conspicuous, porrected from the 
front of the head. The upper branch of the posterior antenne 
four-jointed, and bearing at its termination three plumose setz 
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 sete and aspine. The postero-ventral angle of 
the carapace is fringed with very long sctx of a spine-like 
character. 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 fiir Naturgeschichte’ for 1846, for the reception of a 
remarkable Entomostracan which Miller 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. 
In general characters Acantholeberis is closely—perhaps almost 
too closely—allied to Macrothriv (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 
antenne, and in the peculiar and exceptional structure of the 
long seta of the first joint of the lower branch of the posterior 
antenne. The chief differences are to be found in the number 
of sete on the upper branch of the posterior antenne, which in 
Macrothric are four, but in Acantholeberis only three; and in 
the fact that there is a loop in the intestinal canal of Acantho- 
* This paper appeared also in the Annals and Magazine of Natural History, for June. 
