568 MR FRANK E. BEDDARD ON THE ANATOMY OF OCNERODRILUS. 



with that of the duct. The isolated masses are figured, and it is shown that they have 

 no connection with the duct. 



These latter — although it is stated that their structure is that of the large septal 

 masses which are connected with the duct — are compared to the " Zellenwucherungen " 

 which occur on the dissepiments of Tuhifex and other forms. 



Besides occurring in other Enchytrseids, septal glands are found in the Lumbriculid 

 Phreatothrix pragensis and in Naidium and Pristina. Vejdovsky's statement that they 

 also occur in Criodnlus is not referred to by Eosa [11]. 



Dr Michaelsen, in one of his admirable papers upon the Enchytrseidse [17], notes 

 some important facts with respect to the septal glands of Stercutus niveus. 



The difficulty of discovering the duct is stated to be due to the fact that they can 

 only be properly seen when the glands are in action. The duct is figured (but without a 

 lumen) attached to the dorsal pharyngeal wall. In Mesenchytrseus setosus multipolar 

 ganglion cells were discovered in the interior of the septal glands, and the connec- 

 tion of these with brain explains why the earlier observers regarded the septal glands as 

 ganglia. 



In Ocnerodrilus Eiseni almost the entire space lying between the walls of the 

 oesophagus and the parietes of segments was occupied by the septal glands. 



§ Vascular System. 



I regret my inability to give anything like a complete account of the circulatory 

 organs of Ocnerodrilus Eiseni. This is, however, the less to be regretted, since Eisen 

 has given a tolerably full description, illustrated by one good figure, of the circulation in 

 Ocnerodrilus occidentalis [1, pi. 1, fig. 8]. But if I had been aware that the worms, when 

 they first arrived from British Guiana, belonged to this genus, I should have made 

 greater efforts to study the distribution of the blood-vessels before preserving the speci- 

 mens for microscopical investigation. As it was, the pressure of other work led me to 

 preserve them at once. However, I can say something about these organs, since I 

 succeeded in satisfactorily preserving the worms with acid corrosive sublimate and alcohol, 

 which left the blood-vessels very distinct in sections. 



I quite agree with Eisen in regarding the vascular system of Ocnerodrilus as widely 

 removed from that of the Lumbriculidse. I do not follow him, however, in his comparison 

 with the Tubificidse. This comparison is based upon the presence of the " large pulsating 

 hearts" in segments VIII and IX. It is perfectly true that many of the Tubificidse, e.g., 

 the genus Limnodrilus, are characterised by these vessels. But Eisen did not mention 

 that, as his enumeration of the segments of the Oligochaeta differs from that of Claparede, 

 who first distinguished Limnodrilus [19] from Tuhifex, the position of the hearts is really 

 different ; according to Eisen's figure, they are in segments IX and X in Ocnerodrilus 

 (VHIth and IXth setigerous segments). 



