TEREESTEIAL LSOPODA OF NEW ZEALAND. 11!) 



Genus 2. Haplophthalmus, Scliobl. (1860). 



Haplophthnhims, Sars, Crustacea of Norway, ii. p. 10(i (1899). 



Goiicvlc characters.—^' Body ohlont;'. moderatoly convex, sciilptuvcrl dorsally Avitli 

 morp or loss distinct longitudinal r-ilts, Ceplialon with tlio front triangularly produced, 

 tlioiigh scarcely defined fi'om the ejiistome ; lateral lobes i-ather large. Side plates of 

 mesosome lamellarly expanded, discontiguous. Metasorae not abruptly contracted, 

 epimeral plates of the two anterior segments small, those of the three succeeding ones 

 well developed, laminar; last segment of a similar shape to that in the two preceding 

 genera [Trichoiiiscus and Trichoniscoides\. Eyes very small, simple, subdorsal. 

 AntennuUiR and antenna? much as in Trichou/sciis. Oral ])arts likev/ise rather similar, 

 except that the terminal part of the maxillipedes is obscurely 5-articulate, and the 

 epignath simple, lanceolate. Legs short and thick, scarcely at all increasing in length 

 posteriorly. First pair of pleopoda in female very small and rudimentary ; those in the 

 male well developed, with the inner ramus strongly produced, biarticulate, terminal 

 joint spiniform ; inner ramus of second pair in male likewise produced, triarticulate, 

 last joint narrow, styliform. Uropoda with the inner ramus originating inside a broad 

 expansion of the basal j^ai't, and terminating, as in the genus Trichonisco'ules, in a single 

 slender spine." [Sars, I. c. p. 166.] 



The genus is represented in New Zealand by the following species only : — 



1. Haplophthalmus Helmsii, sp. nov. (Plate 12. fig. 3.) 



Specific description. — Oblong-oval, about twice as long as broad ; strongly convex, 

 the central portion being raised somewhat abruptly above the epimeral portions; 

 epimera well developed and somew^iat wddely separated. Cephalon with the lateral 

 lobes large ; on the dorsal surface between the eyes are two rather large, rounded, 

 roughened tubercles ; surface in front of tliese sloping, rough and uneven : front bhmtly 

 triangular. All the segments of the mesosome bear at the outer border of the central 

 poi'tion a I'aised rounded ridge ; posteriorly this becomes more marked, and on the 

 seventh segment the ridges end in two well-marked tubercles projecting backwards a 

 little over the metasome ; on the fourth anterior segments of the mesosome there is on 

 each side a smaller and less-marked ridge internal to the one already described and 

 parallel to it. Metasome rather small, not quite one- fourth the length of the body ; 

 first three segments short and without epimeral expansions, fourth and fifth segments 

 longer and with well-developed epimera ; last segment very short, more than twice as 

 broad as long, posterior border sti'aiijht. Siu-face of metasome rough like tliat of the 

 wliole body but without distinct rido-es or tubercles. 



Antennse short, not quite one-fourth the length of the body, rather stout ; fourth 

 segment of peduncle a little expanded, shorter than the fifth, which is narrowed at base, 

 all with appressed scales and a few short setae, one or two longer setae on the fifth joint ; 

 ilagellum as long as the fourth joint of peduncle, of three joints, ending in a pencil of 

 long hairs. 



Legs of tlie usual character, short and rather stout, not visible in dorsal view; dactylar 



