THE OLIGOCHJETA OF THE SPITSBEKGEX EXPEDITION. 1109 



49. The Oligochaeta of the Oxford University Spitsbero-en 

 Expedition. Bj J. Stephenson, M.B., D.Sc, Lecturer 

 in Zoology, Edinburgh Universit3^ 



[Received October 9, 1922 ; Read November 21, 1922.] 



(Text-figures 1-6.) 



(Eesults of the Oxford University Expedition to Spitsbergen, 

 No. 20.) 



Contents. 



Page 

 Introduction 1109 



Zoogeograpliical Relations 1111 



On the " Peptonepbridia " of the Encliytrseidse 111.3 



The Genus Henlea 1116 



On the Relations of the Genera Liimhrioilhis and JEncJiytrcetis 1118 



Periods of Sexual Maturity 1118 



Parasitization 1119 



Systematic 1119 



Fam. NAIDIDJ3 1119 



Genus Nais 1119 



Naisjosinee Vejd 1119 



Fam. ENcnTTEJ3iD2E 1119 



Genus Senlea 1119 



H'enlea {Henleanella) heleotroplnis, sp. n 1119 



Henlea {Henlea) hrucoi, sp. n 1121 



Henlea {Henleanella) sp. (1) 112.5 



Henlea {Hepatogaster) sp. (2) 1126 



GieuvL^ Lumhricillus 1126 



Liimhricillns (sgialites, sp. n 1126 



Lumhricillus necrophagiis, sp. n 1130 



Geniis KnchytriBus 1 1 33 



JSii.rhytraus alhidus Heiile 1133 



ISncliytrfBus ci'ymodes, sp. n 1133 



Hncliytreeus sp 1 1 35 



Genus Ilesenchytrceus 1136 



Mesenchytrceus sp 1136 



References to Literature 1137 



Introduction. 



The 01igochg3ta obtained by the Oxford University Spitsbergen 

 Expedition were contained in fifteen tubes — four from Bear Island 

 a,nd the remainder from Spitsbergen. The specimens from Bear 

 Island belonged to two species — JEnchytrceus alhidus Ilenle and 

 JSfais josince Vejd., — both well known. Of thos*^ from Spitsbergen , 

 a number were sexually immature and therefore indeterminable 

 [Mesenchytrceus sp., two species of Henlea, Enchytrceus sp.) ; the 

 remainder, most of which occur in more than one of the tubes, 

 comprise two species of Henlea, one of Enchytrceus, and two of 

 Lumbricillus, all apparently new. With the exception of the 

 xVais from Bear Island, all the worms thus belong to the family 

 Enchytrasidpe. 



Proc. Zool. Soc— 1922, No. LXXIV. 74 



