’s RIJKS MUSEUM VAN NATUURLIJKE HISTORIE — LEIDEN. 281 
and a half as long as 6th and almost as long as 5th and 6th com- 
bined. 
Eyes of moderate size, transverse diameter as long as or slightly longer 
than axial, ocellus large, elliptical, in contact at its anterior extremity 
with the cornea (in Plesion. exigua axial diameter longer than transverse, 
and in Plesion. rostricrescentis the ocellus has a circular form). Antennu- 
lar peduncle reaching to the middle of the antennal scale, which is one- 
fifth shorter than the carapace, 4,4-times as long as wide and which 
distinctly narrows anteriorly; stylocerite reaching to the middle of 2nd 
antennular article (in Plesion. rostricrescentis it reaches to the distal ex- 
tremity of the peduncle). 
Legs of 2nd pair unequal, like in the mentioned species, and, like in 
Plesion. binoculus, also the merus and the anterior half of the ischium 
are annulated. Propodi of the three posterior legs once and a half as 
long as the carpi; dactyli short, measuring hardly more than one-fifth 
of the propodi and of a stout Sabe S-times as long as broad at base 
(in Plesion. binoculus the dactyli measure one-third of the propodi and 
are of a slender form). 
Length of ova-bearing female 53 mm. from apex of rostrum to extre- 
mity of telson. 
Peripandalus nov. gen. 
Upon my request Professor EB. Ehrenbaum of the , Fischerei-biologische 
Abteilung des Zoologischen Museums” in Hamburg has been so kind to 
examine for me the single type specimen of Pandalus serratus from 
Upolu, which has been described in 1874 by A. Milne Edwards in: 
Journal des Museum Godeffroy, Heft IV, p. 11 and figured by the same 
author in the rare work, entitled „Recueil de Figures de Crustacés nou- 
veaux ou peu connus, Avril 1883”, Plate 24. The examination proved 
that the external maxillipeds are not provided with an exopodite, that 
there are no epipods on the peræopods, that the basal lobe (stylocerite) 
of antennules is rather pointed, though rounded at the tip, and fourthly 
that the upper edge of rostrum is armed with fixed teeth only. It 
appears therefore impossible to refer this rare form to any one of 
the known genera of Pandalidae, for, though agreeing with Pandalus 
Leach s.s. and Pandalina Calman in the lack of an exopodite on the 
external maxillipeds, it differs from both by the absence of epipods on 
the legs and by the teeth of the upper edge of the rostrum being all 
fixed, not movable. The stylocerite moreover is not broad, but En 
ed Like in Pandalus and Pandalina the second pair of legs are 
unequal, one is multiarticulate, while the other shows in the dou 5 
