208 OLIGOCHAETA 



transverse vessels witli blind contractile appendages (exc. Stylodrilus ^). Two 

 pairs of sperm-duets (exc. Alluroides) uniting to open by a single spermiducal 

 gland on each side, which lies in front of oviducal pores. "So penial setae. 



It contains only eight well-characterized genera, viz. Lumbriculus, Rhynchel'niis, 

 Trlchodrilus, Stylodrilus, Claparedilla, Phreatothrix, Edipidrilus, Alluroides, and 

 Sutroa ; to these should, perhaps, be added Pseudolumbriculus. There are, however, 

 several imperfectly described genera which may very possibly belong to the same family. 



Vejdovsky (24) places here Gkube's genera Bythonomus and Lycodrilus, more doubtfully 

 CzEBNiAVSKY's genus ArcMeodrilus. They are, however, all ranged by Vejdovsky, as well as by 

 Vaillant (6), as ' incertae sedis.' Bythonomus possesses blind appendages to the dorsal vessel, which 

 character led Vejdovsky to associate it with the Lumbriculidae. The position of Czerniavsky's 

 genus Archaeodrilus is more doubtful. There is nothing in the diagnosis of the genus or in the 

 description of the two species to prove that the genus is a Lumbriculid. 



The two distinctive characters of the family, which are not found in any other 

 family or genus, are the contractile appendages of the blood-vessels, and the 

 arrangement of the vasa deferentia. 



As to the contractile blood-sacs, they have been described by most of those 

 authors who have treated of the anatomy of the Lumbriculidae ; by Grube (9), (who 

 mistook them for diverticula of the intestine), by Clapakede (2), Ratzel (3), 

 Vejdovsky (24), Vaillant (6), Dieffenbach and Eisen (23, 5) ; they are figured 

 by CLAPARi:DE (for Lumbriculus), Vejdovsky {Claparedilla, Phreatothrix, Rhynchelmis, 

 and Lumbriculus), Eisen (Sutroa, Eclipidnlus), and Vaillant (Lumbriculus). Their 

 , arrangement differs in various genera ; in all they consist of either simple, or branched, 

 caecal diverticula of the dorsal vessel or of the perivisceral vessels ; they are covered, 

 like the dorsal vessel, with chloragogen cells, loaded with dark granules — a fact which, 

 as Dieffenbach has pointed out, probably led Grube to regard them as diverticula 

 of the intestine. They are contractile, and, as they lie freely in the coelom, their 

 position alters with each movement. I have already treated of the probable 

 homologies of these organs. 



The sperm-ducts and the spermiducal glands of the Lumbriculidae differ from 

 those of most other Oligochaeta. There are nearly always (not in Alluroides) two pairs 

 of sperm-ducts which open into two consecutive segments, generally the ninth and 

 tenth. The sperm-duct, which communicates with the anterior funnel, opens directly 

 into the ciliated spermiducal gland, the orifice of which is placed upon the tenth 

 segment; the second pair of funnels open into the tenth segment, and are closely 

 attached to its posterior septum ; the sperm -duct traverses this septum directly it 



' And probably Alluroides. 



