798 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XVII 



The dorsal blood-vessel is anteclitellian in origin and does not seem to be 

 connected at its point of origin with any dorsal diverticulum of the gut such as 

 exists in Buchholtsia. It arises in the eleventh segment. I could see no " heart 



body." 



The exact origin of the dorsal vessel is rather difficult to locate exactly in this 

 very minute Enchytrseid. I fix the eleventh segment as the point of emergence 

 from the intestinal plexus, since the vessel is very much broader here than in 

 the dorsal region of the blood-plexus posteriorly* and stands out more from 

 the walls of the gut. The vessel is, in fact, in this segment quite twice the 

 width that it is anteriorly to the point in question. Commonly, for example 

 in Henlea nasuta, the dorsal vessel is much wider at its emergence from the 

 intestinal plexus than it is anteriorly. 



This is confirmed by an examination of a series of transverse sections from 

 which it was evident that the dorsal vessel stood away from the walls of the 

 intestine in the anterior part of the clitellum ; it was indistinguishable 

 posteriorly. 



Concerning the reproductive organs, it may be observed, in the first instance,, 

 that the position of the various ducts and pouches is perfectly normal. The 

 external orifices of the atria are very conspicuous upon the ventral surface 

 of the twelfth segment, in line or nearly so with the ventral setae of that 

 gegment. These setae are, however, absent, and there are no penial setae of 

 any kind. The testes and the ovaries occupy their usual segments, i.e., xi and 

 sii. Concerning the exact form of the sperm-duct funnel I am unable to give 

 details ; but I have identified them and satisfied myself that they are of the 

 usual enchytraeid pattern. 



The spermathecae offer characters of obvious systematic use. They open 

 on the one hand into the oesophagus in the fifth segment, and on the other 

 by a muscular duct on to the line dividing segments iv. and v. I could not find 

 any diverticula. There are but a single pair of spermathecae. 



In the above description I have only been able to dwell upon a certain 

 number of facts which are of systematic importance in the group. Of impor- 

 tance in determining the genus are : (1) the presence of four bundles of 

 curved seta? on all the segments of the body, save the first and the twelfth ; 

 (2) intraclitellian origin of dorsal vessel ; (3) absence of any diverticula to 

 oesophagus ; (4) simplicity of spermathecae and their communication with 

 oesophagus. 



Of the thirteen genera allowed by Michaelsenf, 9, viz., Achceta, Michaelsena,. 

 Mesenchytrceus, Chirodrilus, Buchholtzia, Enchytrceus, Stercutus, Marionina, and 

 Lumbricillus, are excluded by these characters. Though I did not find any 



* It must be borne in mind that Pierantoni (" Studii anatomici su Michaelsena 

 macrochaeta, Pierant, " Mitth. Zool. St. Neapel, xvi. 1903, p. 402) traces a distinct 

 dorsal vessel in the intestinal plexus posteriorly to the region wfcere the former is said to 

 commence. But this does not affect the point of emergence. 



t Oligochseta, in ' Das Thierreich ' (Berlin, 1000). 



