134 Macueay Memortat Vouume. 
the oviduct and yolk reservoir. The cirrus (Plate xt. fig. 14) was entirely unlike 
that of 7: fasczata, closely resembling that of the New Zealand species, only slightly 
curved, and with but a small introvert with exceedingly fine spines. The oviduct 
(vagina) had a zone or circlet of what appeared like rudimentary chitinous teeth. 
2. TemnocerHata comes. Plate xu. figs. 15 and 16. 
This species is a good deal smaller than 7° fasczata, and is at once distinguishable 
from it by the absence of pigment, giving the animal an opaque white appearance, 
and by the invariable presence of six tentacles. The eyes also are much smaller than 
in 7. fascrata, but in most other external features there is a tolerably close 
resemblance. In the internal organisation the chief difference is in the form of the 
introvert of the cirrus, as represented in figures 15 and 16. Both pairs of testes, 
which are small and rounded, are situated far back—one close to the posterior border 
of the intestine, the other behind the latter altogether. This species lives side by side 
with 7. fasctata on the surface of Astacopsis serratus, but usually about the bases of 
the appendages and in the crevices. When I wrote my previous account of ‘Temno- 
cephala, I took those for the young of 7. fasczata, and a batch of their eggs containing 
six-tentacled embryos for the eggs of the latter species ; I was therefore led to the 
conclusion that the latter form had six tentacles when it emerged from the egg and 
was devoid of pigment, whereas in the species in question the pigment appears before 
the young Trematode leaves the egg, and there are from the first only five tentacles. 
The eggs of the present species are of similar shape to those of 7. /fasczata and 
little, if at all, smaller ; in several cases an egg was found zz wtevo. A good many 
specimens were found to be abnormal in the structure of the reproductive organs, and 
many of them had parasitic Nematodes or their eggs or embryos lodged in the testes, 
the receptaculum seminis or the uterus ; one was found without any eyes, in another 
the eye was only developed on one side. In most of the larger forms the alimentary 
canal contained a red granular matter ; in the smaller individuals the contents were 
simply mud, with numerous sand-grains, diatom-valves, &c. ; and in none were there 
found the entire small Arthropods that form the principal food of 7. /asczata and 
T. minor. 
3. TEmNocePHaLa Minor. Plate xu. figs. 2, 8 and 9; Plate xv. fig 1. 
Temnocephala minor, Haswell, l.c., p. 284, pl. xx. figs. 4 and 5. 
This is a comparatively small species, being rarely, when fully extended, more than 
a fifth of an inch in length, and being relatively slender. There are, as in 7. fasczata, 
five subequal tentacles. The general colour is grey. The pigment, which is almost 
entirely confined to the dorsal surface, is disposed in a network of narrow lines with 
