270 OLIGOCHAETA 



of the reproductive organs does not materially differ from that of Tubifex or Limno- 

 drilus ; the spermidueal gland is short and the sperm-duct rather long ; at the point 

 where the solid prostate is attached to the former it (the spermidueal gland) is some- 

 what dilated. There is only one species of the genus. 



Lophochaeta ignota, Stolc. 

 L. ignota, Stolc, Abh. k. Bohm. Ges. 1888, p. 41. 

 Definition. Pectinate setae of dorsal bundles, u-ith four prongs and a weh. CJdimous penis 

 conical in form. Hah. — Bohemia. 

 It is a curious fact about this species that no spermatophores have been found. 

 The spermatheca are pear-shaped pouches, there being no constriction between the 

 pouch and its duct, such as developed in Limnodrilus. 



Genus Beaktchiura, Beddaed. 



DEPiiiriTiOM'- Posterior segments with a series of contractile toranehial processes in 

 dorsal and ventral median lines, a pair to each segment. Setae capilliform 

 and uncinate, capilliform setae in dorsal bundles of anterior segments only. 

 Two pairs of enlarged circular vessels (hearts) in IX and X. These and 

 anterior perivisceral loops contractile. Dorsal vessel ventral in position in all 

 segments after the twelfth. 



This very remarkable genus of Tubificidae was found by myself in the 'Victoria 

 regia' tank in the Botanical Society's Gardens, Regent's Park, London, and described 

 with illustrations in the Quarterly Journal of Microscopical Science. It agrees 

 with Hemituhifex and some other genera in the form of the setae, but differs from all 

 Tubificidae except Hesperodrilus branchiatus in possessing branchiae, and from all 

 Oligochaeta in the form of those branchiae. They consist of a series of pairs of 

 cylindrical processes arising from the middle dorsal and ventral lines ; each branchia 

 has a capillary loop lying beneath the epidermis and a layer of muscles ; the cavity of 

 the branchiae, which is shut off from the general body by a diaphragm, is lined by 

 peritoneum and traversed by muscular strands. The branchiae move actively during 

 life, and can be extended and retracted. The circulatory system, like that of Ilyodrilus 

 and some other genera, has in addition to the dorsal and ventral vessels a supraintestinal 

 trunk, and, as in Ilyodrilus and Teltnatodrilus, there is an integumental network of 

 blood-vessels. All the perivisceral trunks of the segments in front of and including 

 the tenth are contractile, those of the ninth and tenth segments being specially enlarged. 



