48 CRUSTACEA MALACOSTRACA. III. 



spines on the lower side; sixth joint slightly thickened and much narrower than the fifth, about three 

 times as long as deep, and with some shorter spines at the lower margin; seventh joint moderately 

 robust, half as long as the sixth; claw scarcely as long as in Munna. (The other legs lost in my 

 specimens). 



Abdomen (figs, i f and i h) broad, but posteriorly considerably produced, and it differs much 

 from Munna in the insertion of the uropods. These appendages are unfortunately lost, but they must 

 have been very robust and probably long, as their very large insertions protrude on the upper part of 

 the sides and partly dorsally as vaulted parts, with their cup-shaped end turning backwards, somewhat 

 outwards and distinctly downwards. The female operculum (fig. i g) is somewhat broader than long, 

 and tapers from much before the middle to the moderately broadly rounded end. The median lamella 

 of the male operculum somewhat reminds one of that in Munna groenlandica, but the end of each 

 pleopod is much more deeply cleft, divided into an inner lobe and an outer process (figs, i h i i). 



Remarks. Pseudomunna, which in general appearance is rather similar to Munna, differs 

 sharply from this genus in the antennulae, in the much longer proximal joints of the antennae, in the 

 more narrow joints of the maxillipeds, in the shape of first pair of legs, finally in having the abdomen 

 produced posteriorly and with very large and protruding semidorsal insertions for the uropods. - - In 

 some of these characters Pseudomunna is allied to Dendrotion, and it is certainly rather closely allied 

 to a very curious animal, the antarctic form Mormomunna spinipes Vanhoffen (1914), but at least the 

 median lamella of the male operculum differs so much in the two genera that they cannot be united. 



Only one species is known. 



30. Pseudomunna hystrix n. sp. 

 (PI. IV, figs. la-ii). 



Description. Head nearly as in Munna Hanseni, but the ocular protuberances are still lower 

 (fig. i a) and apparently without facets. Antennulee in the male (fig. i b) a little more than half as 

 long as the animal; first joint somewhat inflated but yet much longer than thick; second joint some- 

 what shorter than the first, rather slender, with an extremely long and strong seta at the end; third 

 joint slender and nearly twice as long as the second; the flagellum more than half as long again as 

 the peduncle, i7-jointed, with the first joint quite short and the second very long. In the female the 

 antennulae were lost, excepting their two proximal joints (fig. i a), which differ but little from those in 

 the male. Third and fourth joints of the antennce have some very strong, nearly spiniform, long 

 setae on the inner side near the end. 



The thoracic segments somewhat remind one of those in Munna acanthifera, but the four 

 anterior segments have a much stronger armature. Each of these segments has on the upper surface 

 (fig. i a) a number of rather irregularly distributed protuberances shaped as cones cut off; some among 

 these cones are small, while others are much thicker and higher, and each cone serves as the foot for 

 a spine; most of these spines are lost or broken near the base, but two or three remain, and they are 

 long, strong, a little curved and adorned with some small, spiniform lateral processes; at the lateral 

 margin each of these segments has a couple of such spiniferous cones, and similar protuberances are 

 found on the coxae. The three posterior segments have very little armature excepting near the lateral 



