REPORT ON THE SCHIZOPODA. 119 



even actually burdensome to ovigerous animals, as the ovisacs would to a very consider- 

 able extent interfere* with tlicir free mobilit}^ ; hence their develojiment in the females is 

 quite arrested in that region, whereas in the male they are retained, as usual, on all 

 the legs, except the last (see PI. XXI. figs. 1,5). Of the northern species, Nyctii'ihanes 

 couchii, Bell ( = Nyctiphanes norvegica, M. Sars ?), an ovigerous specimen has on one 

 occasion oidy been observed, viz., by Professor Bell, in whose well-known work on the 

 British Stalk-eyed Crustacea, the ovisacs are recorded and figured as two rotund sacs 

 depending freely from the posterior part of the trunk. The form and arrangement of the 

 ovisacs in the two species accordingly exhibit well-marked differences, though agreeing 

 in their being not confluent, as is the case in other forms of Euphausidians. 



As regards the luminous apparatus, the number and arrangement of the globules 

 perfectly agrees with that described above in the genus Euphcmsia. 



Habitat. — Of the present species rather numerous specimens, besides some few larvae 

 in a very early stage of development, to be described further on, ^\-ere collected in three 

 difi'erent localities off the Australian coast. All the specimens were taken in the surface- 

 net, and in most instances at night. The localities were as follows : — 



With respect to distribution, the species would accordingly appear to be wholly 

 confined within the limits of the Australian Seas. 



Genus 5. Thysanoessa, Brandt, 18.51. 

 Thysanoessa, IJrunlt, Middendorf's sibirische Reise, Zoologie. 



Generic Characters. — Body more or less slender, tapering posteriorly. Cai-apace short, 

 distinctly rostrate, antero-lateral corners produced. Eyes of somewhat irregular form, 

 cornea divided, as it were, into two segments by a transverse constriction. Flagella of 

 both pairs of antennae very short. Antennular peduncle without any dorsal leaflet, 

 basal joint much flattened, the two other narrow and elongate. Terminal joint of 

 second pair of maxillae comparatively small, exognaths in both pairs well developed. 

 Maxillipeds slender, not very elongate. First pair of legs very strongly developed, and 

 much longer than the rest, geniculate, meral and cai-pal joints very elongate and nearly 

 naked, propodal joint compressed, and provided on both edges with strong, spiniform 



