230 



OLIGOCHAETA 



almost obliterated lumen. None of these genera possess penial setae, which are only 

 found in Ilyodriius and Bothrioneuron ; indeed the ventral setae of the eleventh 

 segment, upon which the male pores are situated are altogether absent from the 

 sexually mature worm. It is not altogether easy to compare the efferent apparatus 

 of the various genera of Tubificidae among themselves. 



Fig. 38. 



MALE EFFERENT 

 APPARATUS OF 

 LOPHOCHAETA. 



(After Stole.) 



i. Funnel. 2. Penis. 3. 

 'Atrium.' 4. 'Prostate.' 

 5. Coiled sperm-duet. 



Fig. 40. 



Fig- 39- 



ILYODHILUS COCCINEUS. 

 MALE EFFERENT APPARATUS. 



(After Stole.) 



i. Funnel. 3. Sperm-duct. 3. Penis. 

 4. Muscles for its retraction. 5. 



Glandular covering of 6. ' Atrium.' 



BOTHRIONEURON VE.TDOVSKYANUM. 

 MALE EFFERENT APPARATUS. 



(After Stole.) 



i. Proximal region of 'atrium.' 2 ' Para- 

 trium.' 3. Distal region of ' atrium.' 4. Peninl 

 setae. 5. External pore. 6. Muscles for pro- 

 trusion of distal end of efferent apparatus. 

 7. Muscle attached to sperm-duct (8). 9. Funnel. 



The simplest form is unquestionably that of Ilyodriius, which leads to the Naids 

 and Lumbriculidae. 



If it were not for Branchiura, the more specialized chamber of Tubifex, &c., 

 might be regarded as produced by further differentiation of the simple globular sac 

 of Ilyodriius, particularly since, as VEJDOVSKY pointed out, the complex terminal 



