Haswett—A Monograph of the Temnocephatlee. 135 
meshes of irregular shape, not covering the whole surface, but leaving considerable 
spaces entirely free. The pigment-cups of the eyes appear as a special condensation 
of the pigment, continuous with the general network. A noteworthy feature of the 
integument already alluded to is the presence of vibratile cilia in the region behind 
the tentacles. The alimentary canal has seven or eight well-marked constrictions, 
which correspond with incomplete muscular septa. The anterior testis extends a 
little further forward than the middle of the intestine. The posterior testis has its 
anterior end considerably in front of the posterior end of the latter; its posterior 
end is a little behind the genital aperture.* Both testes are very distinctly divided 
laterally into lobules by transverse incisions. There is a well-developed, narrow, 
curved ejaculatory sac, which is sometimes as long as the cirrus. The latter (Pl. xu. 
fig. 8) is very gently curved, wide at the base, narrowing distally, with a very definite 
terminal segment or introvert, wider than the part of the organ which immediately 
precedes it, and containing on either side a large number of fine spinest. There are 
no teeth in the vagina. 
This species occurs on the surface of the widely-distributed small Australian 
crayfish—A stacopsts bicarinatus—of which it is aconstant companion. Its habits are 
similar to those of Z. fasciata. The pear-shaped eggs, supported on short stalks, are 
attached most commonly to the sternal surfaces of the abdominal segments of the 
crayfish, sometimes to the lateral parts of the cephalothorax, or the bases of the 
antennules, eye-stalks and antenne. 
4. TemnocepHaLa Denpyi. Plate x. figs. 8, 12, 17 and 18; Plate xu. figs. 5 and 6; 
Plate xu. figs. 7 and 11; Plate xi. fig. 1. 
This species is usually somewhat larger than 7. mznxor and rather broader in 
proportion to its length (about ‘5 em.), It is entirely devoid of pigment, with the 
exception of a few scattered granules in the eyes ; the eyes are smaller than in 7. 
minor, With shallower pigment-cups, the openings of which are directed outwards. 
In other respects the general external appearance is similar to that of the latter 
species, and there are five tentacles. In internal structure also there is a very 
considerable resemblance. There are ten to twelve constrictions in the intestine. 
The chief internal difference is in the male reproductive apparatus. The posterior 
testis is situated much further back than in 7. mznor, its anterior border being about 
on a line with the generative opening. Both testes are lobed. The vesicula 
seminalis is much narrower. But the most important difference is in the cirrus, 
* These relations vary a good deal, naturally, according to the condition of the specimen. 
+ The Nos. of figs. 9 and 10 of Pl. xxir. in my former paper have been inverted ; fig. 10 is intended to represent the 
cirrus of 7’. minor, but none of the cirri, except that of 7. fasciata, are adequately represented, the arrangement of the 
spines not having been understood. 
