10 
AUSTRALASIAN ANTARCTIC EXPEDITION. 
from ten to fourteen vertical articulations on the sixth joint of the thoracic legs, a 
number which has so far only been met with among the Mysini. It is obvious, therefore* 
that this character cannot be used as a differentiating character of the various tribes 
of the sub-family. 
Among the genera assigned by Hansen to the tribe Leptomysiiii, Tenagomysis 
approaches perhaps most closely to the genus Leptomysis , differing only in the form of 
the telson. The latter, indeed will serve to distinguish the genus from all its congeners. 
Its general form is strikingly like that found very frequently among the Mysini, especially 
such genera as Macromysis and Schistomysis, with the important difference that in the 
latter genera there are no plumose setae in the centre of the clefts of the telson, whereas 
Tenagomysis possesses a pair in that position. These setae are entirely absent in the 
genera of the Mysini, characteristic of the Erythropini, and present in Mysideis and 
Mysidopsis alone of the genera belonging to the Leptomysiiii. Tenagomysis thus 
presents small features characteristic of three of the tribes of the sub-family Mysinae. 
Tenagomysis tenuipes sp. nov. 
(Plate XVIII, figs. 1-7.) 
Locality. —Carnley Harbour, Auckland Islands, 24th June, 1912, one adult d, 
21 mm. 
Description. —General form moderately slender; carapace having the anterior 
margin produced into a triangular rostral plate which extends for about one-third of 
the way along the basal joint of the antennules and is shorter than the eye; rostral 
plate (fig. 1) about three-fifths as long as broad at its base, apex obtusely pointed; last 
two segments of the thorax left completely uncovered by the carapace. 
Antennular peduncle (fig. 1) rather elongate, about as long as the sixth segment 
of the pleon; basal joint about as long as the second and third combined; second 
joint very short; third joint with a prominent spine on the dorsal anterior margin 
between the bases of the flagella; latter very long and slender; the basal joint has a 
few setae on the outer distal corner; male appendage well developed and densely 
hirsute. 
Antennal peduncle (fig. 2) not as long as the basal joint of the antennular peduncle, 
second joint slightly longer than the third. 
Antennal scale (fig. 2) exceedingly long and narrow, extending for one quarter 
of its length beyond the distal end of the antennular peduncle, eleven times as long as 
broad, narrowly lanceolate in shape, setose all the way round, distal joint exceedingly 
small but distinctly present; the basal joint from which both the scale and peduncle 
spring, bears on its lower surface two strong spines, an inner and an outer, under the 
base of the peduncle and scale respectively. 
Thoracic legs. —The form of the endopocfs of the first and second thoracic limbs is 
shown on plate XVIII, figs. 3 and 4. They present no special points. The basal joint 
