152 



TERRA NOVA" EXPEDITION. 



19. Diastylis neozealanica, G. M. Thomsou. Fig. 6. 



jD. neo-zealanica, G. M. Thomson, 1892, p. 268, pi. xviii, figs. 1-11 ; Caiman, 1908, p. 239. 

 Diaatylopsis neozealanica, Stebbing, 1913, p. 110. 



Occurrence. — Station 133. Spirits Bay, near North Cape, New Zealand. Plankton, 

 20 metres depth. One male. 



Remarks. — The .solitary male specimen is imperfectly preserved, and is only 

 referred to Thomson's species (of which no male has yet been recorded) because the 

 ridges on the carapace are arranged as in the female specimen in the Museum collection 

 which I have mentioned (Lc.) as belonging to this species. From the female it differs 



in the characters proper to its sex, and it is to be 

 noted, in particular, that the flagellum of the 

 antennule has the conspicuous spurs described in 

 D. insularum at the end of the basal segment 

 (Caiman, 1908, p. 237, figs. 5 and 5a). The 

 accompanying figures show the disposition of the 

 ridges of the carapace in the " Terra Nova " 

 specimen. 



In the neighbourhood of this species I would 

 place a specimen obtained by the " Discovery " at 

 the Auckland Islands, and mentioned but not 

 described in my report on the Cumacea of that 

 expedition. The specimen is in very poor con- 

 dition, having apparently sufi"ered drying, and the 

 carapace, in particular, is so crumpled that its 

 sculpturing can no longer be distinctly traced. 

 All that can be said is that the appendages show 

 a general agreement with D. neozealanica and 

 D. insularum, but that the carapace is not 

 minutely spinous as in the latter species, while 

 the ridges are apparently much less conspicuous 

 than in the former. 



Stebbing {I.e.) states of D, insularum that it 

 " seems to be a variety of D. neozealanica." I do 

 not know on what grounds this opinion is based, and it would require the examination 

 of better-preserved and more abundant material than is at my disposal to confirm or 

 disprove it. The species are certainly closely allied, as is shown by the characters of 

 their appendages, but in the form which I described as D. insularum the carapace is 

 minutely spinous, with a scarcely perceptible ridge or line of spinules on the side of 

 the carapace, while in the specimens that I refer to D. neozealanica the surface of the 

 carapace has three oblique lateral ridges, and apart from these is quite smooth. 



A. 



Fig. 6. — Diastylis neozealanica, G. M. 

 Thomson. Male. A. Side view, 

 B. Dorsal view, of carapace. X 25. 



