350 KARM NARAYAN BAHL 
1. INTRODUCTORY. 
Tue blood-vascular system of earthworms has engaged the 
attention of many distinguished observers. Lankester (12) 
described the blood-vessels of Lumbricus in one of his 
memoirs on the ‘Anatomy of the Earthworm’, which forms 
about the earliest contribution to this subject. Jaquet (9) 
gives a comparative account of the vascular system in Annelids, 
describing the system in typical genera of the various classes 
of the group. Of the Oligochaeta, he selects Lumbricus 
as a type. Perrier (18) and Benham (5), also working on 
Lumbricus, describe the course of flow in all the blood- 
vessels from a study of the disposition of the valves; to 
Benham we also owe our knowledge of the blood-supply of 
the nephridium in Lumbricus (6). Harrington (8) gives 
a detailed account of the anatomy of the blood-system in 
Lumbricus with elaborate diagrams, and was the first 
to describe the arrangement of blood-vessels in the integument. 
Recently, Johnstone and his student, Miss Johnson (10 and 11), 
have published two papers on the course of blood-flow in 
Lumbricus demonstrating the course in various vessels by 
a series of interesting experiments and observations. ‘The 
blood-system has thus been thoroughly studied in Lumbricus 
since that is the form studied as a type in Europe and America. 
Amongst the Oriental forms of Oligochaeta, Bourne (1) has 
described the blood-system in some detail in the Perichaete 
worm Megascolex and also in Moniligaster grandis 
(2, 1894), a huge worm about two feet long placed by Beddard 
in the group Microdrili. Besides Bourne’s work on Mega- 
scolex, very little attention has been paid to the blood- 
system of the Perichaetidae, the largest family of earthworms. 
The earthworm Pheretima (the genus Perichaeta sensu 
stricto) is now studied as a type of the Oligochaeta in 
Northern India and also at the Universities of Bombay and 
Calcutta, and it has become necessary, therefore, to have as 
complete a knowledge as possible of the anatomy of this form. 
An attempt has been made in this paper to present an account 
