334 ON SOME TKEMATODK PARASITES OF AUSTRALIAN FROGS, 



yolk-follicles may be seen to be loaded with droplets of the 

 material that goes to form the shell (Goldschmidt 26). 



The thick-shelled eggs (0-0022 mm. thick) are oval in shape, 

 04 mm. long, by 0025 mm. broad, are very numerous, and, 

 at first, light brown in colour, gradually becoming very much 

 darker. 



This worm is evidently closely related to Distomum. sociale 

 Liihe, having the same generic characters, and differing from 

 it mainly in the degree of spininess of the body, in the relative 

 size of the suckers, in the rounded instead of triangular shape 

 of the gonads, in the right instead of left position of the ovary, 

 and in the less elongated extension of the yolk-glands. I shall 

 have more to say about its relationships, a little later. 



Mesoccelium megaloon,* sp.n. 



(Figure 15.) 



Diagnosis. — Habit slender and delicate, elongated oval, 

 broader behind, 1-8 mm. long, and 0-358 mm. broad at the 

 widest part; intef/ument smooth, without spines; oral sucker 

 0-1935 mm. in diameter, ventral 0-0645; ratio of oral to ven.' 

 tral, 3:1. Oesophagus moderately long, intestinal limbs short, 

 hardly reaching beyond the ovary. Testes oval, (0181 x 0-129 

 mm.), placed dorsally and laterally in regard to the oral 

 sucker, and extending backwards behind it ; ovary spherical, 

 0-112 mm. in diameter, not quite lateral hut latern-merlian, 

 more on the left side. Yolk-glands with rounded to oval fol- 

 licles, from 0-017 to 0034 mm. in diameter, comparatively 

 uumerous, about 70 on each side; the two lateral groups ex- 

 tending near the dorsal surface across the body to the middle 

 line, but posteriorly not extending beyond the ovary. 



Eggs comparatively large and thick-shelled, average length 

 0-047 mm., varying from 0-043-0052 mm., by 0-029 mm 

 broad. 



/Mcyas, large; (ioi/, egg. 



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