664 OLIGOCHAETA 



This species is much nearer to Pontoscolex than the last, and, indeed, was 

 confounded by Schmaeda with P. arenicola. It is, perhaps, doubtful whether it 

 ought not to be referred to that genus rather than to Diachaeta. The gizzard 

 and the thickened integumental septa are exactly as in P. arenicola; I think also, 

 but am not quite certain, that the caudal zone was present. The cliteUum is 

 further forward than in D. thomasii, and is thus nearer to that of Pontoscolex. 



Subfamily Miceochaetinae. 



Defiwitiom'. Spermathecae (if present) usually in neighbourhood of the female 

 apertures, nearly always minute, and generally many in each segment. Copu- 

 latory papillae, furnished with special glands, and usually with modified setae, 

 present. 



This subfamily is absolutely confined to the Old World, occurring in Africa, 

 Burmah, Madagascar, and some of the East Indies, and in Europe. 



I refer the eight genera, whose chief characters are exhibited in the annexed table, 

 to this subfamily ; all of these genera, however, cannot, as yet, be regarded as 

 established beyond a doubt ; of Bilimba we have at present too little knowledge to 

 assert that it is not synonymous with Callidrilus. The other genera are perhaps 

 distinct ; Benham has expressed the opinion that Kynotus is a near ally of 

 Microchaeta, if not congeneric with it ; there is no doubt that he is right in 

 pointing out that the species of Microchaeta, M. belli and M. papillata, form a link 

 •between the two ; for these two species, like the genus Kynotus, possess copulatory 

 glands which are furnished with modified seta^. Microchaeta, however, difiers in 

 .having no tei-minal glands into which the sperm-ducts open, in possessing one pair 

 of calciferous glands, and in a few other minor characters. 



The four genera, Callidrilus, Bilimba, Annadrilus, and Glyphidrilus, seem to 

 form a natural assemblage in the fact that the setae are not deficient anteriorly, 

 and that the two setae of each pair are separated by a comparatively wide interval 

 anteriorly, while they are strictly paired posteriorly ; in other important points, such 

 as the presence or absence of a spermiducal gland, the existence or non-existence of 

 copulatory glands they disagree. 



Siphonogaster holds an isolated position ; and yet it is not so different as a study 

 of its structure might at first seem to show; the most salient point of difierence, 

 not only from other Microchaetidae, but from the Geoscolicidae in general, is the 

 existence of the two non- retractile penes; these are outgrowths of the body-wall, 

 and it will be noticed that they possess modified setae and glands, such as are 



