192 
Nicholls — Tico New Phreatoicids. 
apines on propod receiving tip of dactyl. In the posterior series 
of peraeopods, the length of the limb and the extent of the expansion 
of the three proximal joints increases progressively, the nieros 
being 2 )i’odiiced into a notable distal lobe. First pleo 2 ‘)od with endo- 
2 >odite and exo 2 )odite of equal length; p]eoi)ods 2-o with endopodite 
overlapping distal joint of exot)odite and with epipodite. Second 
pleopod, in male, with 2 )enial filament, moderately curved, concave 
laterally, strongly setose with a considerable row of stout setae 
a^jically. IJrojiod stout, jiedimcle ex^jaiided on inner margin, very 
spinose on both margins; rami ex^^anded, spinose, inner the longer. 
Spine at base of rami not pectinate. 
Colour: Jn si)irit, yellowish-grey. The liody generally is yellow 
tinted, with black dendritic S})ots scattered sparsely along the sides 
and still more s|)arsely ujion the extremities of the limbs. In mid- 
dorsal line and on either side dorsally, these spots are closely aggre- 
gated to form three dark interru 2 )ted lines. In the t^craeoii these 
may be continuous and almost merge into one another, the marking 
then, in that region, may be described as consisting of a jiaired dark 
dorso-lateral line separated by a light median yellow line bearing 
a dark spot at the middle of each segment. Laterally (externally) 
the dark bands may bo defined by a thin and wavy yellow line. 
Ske: The largest male measured 21 mm., the smallest but 12 
mm., with a width of peraeon of 2.5 mm. About 25 per cent, of 
the sj)ecimens showed no male organ, the largest of these being 
14 mm. in length, with a breadth of peraeon of 3.5 mm.; the 
smallest obtained measured 9 mm. 
Locality: The collection of close upon a hundred specimens was 
made by W. McLennan (in November, 1915) and was presented to 
the Museum by II. L. White, Fsq. The locality label indicates that 
the specimens were taken in a ‘‘small 2 >ool” at Sandstone Bluff, 
Northern Territory. From notes, made by the collector, it -would 
appear that the spot was on, or near, the Wellington Hills, E. long. 
133^°, S. lat. 12°. In other notes, kindly supplied by Mr. Kershaw, 
the pool is described as ‘‘a fine rock hole of clear, cool water. 
Detailed description. This species apparently attains almost 
to the largest size recorded for living aquatic Phreatoicids.* Of the 
mature o vigorous female there are no S2)ecimens, the largest female 
ill the collection reacliing a length only two thirds that of the 
largest male. In this respect, this S 2 )ecies appears to agree with 
^Its length is equalled, peiliaps exceeded, by large examples of P. 
kirkii, var. dunedinensis, Chilton, which is said to reach 22.5 mm., 
and by P. spinosus, Smith (15-25mm.). My largest specimen 
of A. Untoni measured 20 mm. The fossil form P. wianamattenis 
had an estimated length of 30 inni. 
