A NEW GENUS OF OLIGOOH^TA. 475 



much as these setae have been made use of by myself and others 

 as specific characters. T may recall the fact that in Acantho- 

 drilus Georgianus (5) there is an analogous dimorphism 

 of the penial setae. 



§ The Intersegmental Septa. 



As is so constantly the case among earthworms^ certain of 

 the intersegmental septa are specially thickened, as well as con- 

 nected with each other and with the parietes by muscular 

 bands. 



In the present species the septa between Segments 6 and 

 13 are thus strengthened, there being, therefore, seven. As 

 in other cases, these septa are very concave forwards, the 

 middle region lying much behind the peripheral attached 

 margin ; the septa present, therefore, have the appearance of 

 a series of cups, each fitting within the one which follows it. 



§ Alimentary Canal. 



The gizzard lies in Segment 6 (cf. fig. 14). 



The oesophagus extends as far back as Segment 18; it 

 does not, however, abruptly widen into the intestine, which 

 only commences (fig. 13) in the 20th segment. 



In Segments 15, 16, and 17 are three pairs of calciferous 

 glands. As shown in the figure (fig. 13), each of these glands 

 is divided into two by a transverse furrow. 



§ Nephridia. 



The worm was not in a sufficiently good state of preserva- 

 tion to allow of any observations upon the minute structure of 

 the nephridia. 



So far as could be ascertained by dissection, the nephridia 

 throughout the body appear to be of the " diffuse" type. 



Lying alongside of the pharynx on each side was a con- 

 spicuous glandular body, which is doubtless similar to the 

 salivary gland of Acanthodrilus multiporus, and to the 

 "mucous^^ gland of Urochaeta, Diachaeta, &c. 



