730 



AUSTRALIAN HIRUDIN KA, IV., 



There are present no sensillse in the preserved specimen, so 

 that one has no guide to the metameric constitution of th© 

 species from external examination by means of the sense organs,. 



Fig. 2. — Diagrams of anterior extremity of GeohdeUa tristriata, 

 sp.nov. ; ventral and dorsal. 



except at the anterior extremity, where one can do so where one^ 

 can draw conclusions from the position of the eyes. However, 

 as the number of annuli is exactly the same in all species of 

 GeohdeUa, one may safely conclude that the somitic constitution 

 of the body is the same in this species as in those in which it can 

 be made out by means of the sensillse. It is quite possible (and 

 indeed quite likely) that sensill?e are present in the species, and 

 could be made out in a well fixed specimen. Both G. Whitmani 

 and G. austral iensis bear sensillse. 



According to Whitman's method of determining somite-limits,. 

 by assuming that the sensillse denote the first annulus of a true 

 segment, the constitution of the body in which sensillse can be 

 made out, is as follows : — 



