1A Macuray Memorrat Vouume. 
the character of unicellular digestive glands. In addition there are a few cells 
identical with the excretory cells. 
In all essential respects all the Australasian species agree in the form and 
structure of the pharynx ; any differences that there exist relate only to relative size 
and relative degree of development of the various layers of muscle and of the 
unicellular glands. 
If Weber’s account of the pharynx of 7. Semper? be correct, which I see no reason 
to doubt, we have here another feature in which that species diverges from the others 
in the direction of a greater simplicity of organisation. He describes the wall of the 
pharynx as consisting mainly of circular fibres, with sparsely developed radial fibres, in 
contrast to that of other Trematodes, and endeavours to account for this by the nature 
of the food. But a sucking action in the case of an animal immersed in water is as 
important in drawing whole prey into the mouth as in drawing in blood, epithelial 
detritus, ete.; and it will be seen from the above description that the pharynx of 
Temnocephatla, at least in the Australian species, belongs to the same type as those 
of Polystomum, Calicotyle, Sphyranura, and Pseudocotyle. T. Jheringtt in this 
respect, as In a good many others, appears to approach nearer 7. Semper. 
Brandes refers to the structure of the pharynx of 7. dvevicornis, and figures a 
section.* He recognises the anterior and posterior masses of transverse fibres, 
previously overlooked, and lays stress on their importance as corresponding with the 
sphincters of the pharynx in the Ahaédocela. The muscular fibres he characterises 
as hollow—an appearance which, as I have elsewhere pointed out, is prolably due 
to the condition of his material. 
The pharynx of Plagzostoma Lemani, as described and figured by Béhmig,t 
approximates very closely to that of Temnocephala. So also does von Graft’s 
“pharynx bulbosus rosulatus” of most Rhabdocceles, except that the direction of 
the layers is reversed, and that the thick anterior and posterior transverse bands are 
wanting. 
Craspedella differs trom TZemnocephala in the rudimentary character of the 
pharynx. 
Between the pharynx and the intestine, into the short passage which may be 
called cesophagus, there open the ducts of a large number of unicellular glands 
resembling those described in a number of other ectoparasitic Trematodes as salivary 
glands. Neighbouring cells are often coalescent: they have homogeneous protoplasm 
and oval nuclei ‘0075 mm. in diameter. 
* Loc. cit. p. 574, pl. xxi. fig. 20. 
+ Loc. cit. p, 414, and p, 219, fig. 8. 
