DESCRIPTIONS OF GENERA AND SPECIES 187 



setae. It is possibly identical with LEIDY'S Chaetodemus panduratu, also a transparent 

 and colourless species. I could not myself detect even colourless oil-drops. 



(8) Aeolosoma leidyi, CRAOUN. 

 A. leidyi, CRAGIN, Bull. Washburn Coll. Lab. vol. ii. p. 3. 



Definition. Anterior segments with capilliform and sigmoid, posterior segments with sigmoid 

 setae only. Integumental globules pale olive-green. 



As defined, this species can be distinguished from A. tenebrarum by the distribution 

 of the sigmoid setae, which, in the last-mentioned species, are only found in the seta 

 bundles of the posterior segments. 



Group MICRODRILI. 



FAMILY PHREORYCTIDAE. 



DEFINITION. Aquatic or terrestrial Oligochaeta of slender form, often exceedingly 

 long. Setae in four rows of single setae or pairs, sigmoid. Testes in X, XI. 

 Ovaries in XII, XIII, or XIII only. Sperm-ducts, two pairs opening 

 separately, without spermiducal glands Spermathecae in front of testes. without 

 diverticula. No genital setae. 



This family contains at present only two genera, viz. Phreoryctes, which has been 

 long known, and Pelodrilus, recently described by myself. As these genera, although 

 both conforming to the above definition, present numerous structural differences, it will 

 be better to describe them separately instead of giving a general sketch of the anatomy 

 of the family as has been done in other cases. 



Genus PHREORYCTES, HOFFMEISTER. 



Syn. Phreoryctes, HOFFMEISTER. Haplotaxis, HOFFMEISTER. Nemodrilus, CLAPAREDE. 



Georyctes, SCHLOTTHAUBER. 



DEFINITION. Setae in four rows of single setae or pairs. Clitellum XI-XIV. 

 Prostomium divided by a transverse constriction. Testes in X, XI ; ovaries 

 in XII, XIII. Vasa deferentia open separately on to XI and XII; oviducts 

 on to border line between segments XII/XIII and XIII/XIV. Spermathecae 

 two or three pairs in VII, VIII (IX). 



This genus was originally described by HOFFMEISTER (3) under the name of 



B b 2 



