STRUCTURE OP UROCH/ETA AND DTCHOGASTER. 
235 
On Certain Points in the Structure of Urochseta, 
E. P., and Dichogaster, nov. gen., with further 
Remarks on the Nephridia of Earthworms. 
By 
Frank. E. Beddard, HI. .4., 
Prosector to the Zoological Society of Loudon, and Lecturer on Biology at 
Guy’s Hospital. 
With Plates XXIII and XXIY. 
I. The Structure of Urochseta. 
M. Perrier’s elaborate memoir (22 1 ) upon the structure of 
this worm leaves little to he done in the way of general ana- 
tomy. All the principal points which are of importance in 
the systematic grouping of Earthworms are thoroughly de- 
scribed and figured, with the sole exception of the female 
reproductive apparatus, which was not present in the examples 
studied by him. Perrier has also given a most detailed 
description of the vascular system down to the minutest 
ramifications, which forms one of the most complete accounts 
extant of the Annelid circulatory organs. The method of 
study adopted by M. Perrier was almost entirely that of 
laborious dissection, and the results which he has obtained by 
this means are undoubtedly striking. The elucidation of 
many points in the anatomy of Earthworms demands, how- 
ever, a recourse to the section-cutting method, which has been 
adopted by myself in studying this Earthworm. I have, 
therefore, been able to add some few facts to what is already 
known, thanks to Perrier’s researches, of the anatomy and 
histology of Urocheeta. 
1 The numbers enclosed in brackets refer to the “ List of Memoirs ” 
on pp. 279, 280. 
