157 



tending to the \entral side of the buccal cavity, where they He parallel 

 to it. These extend caiidad to the anterior part of IV where they 

 approach each other and unite near IV/V to form the single ventral 

 trunk. Near the middle of III a transverse vessel extends dorsad 

 from each ventral vessel and unites with the dorsal vessel near the 

 posterior part of III. In the anterior part of IV similar transverse 

 vessels connect the ventral vessels with the dorsal trunk. No trans- 

 verse vessels occur in II. 



Ncphridia. — The anteseptal part (PI. X, Fig. 27) is about the 

 same size as the postseptal though there is a slight variation, the latter 

 being sometimes a little larger than the former. The efferent duct 

 arises from the mid-ventral surface of the postseptal part about mid- 

 way of its length and opens to the exterior just anterior to the ventral 

 setae bundles of the same somite. The lumen is very tortuous through- 

 out its entire course. 



Spenniducal Funnel. — This organ (PI. X, Fig. 29) lies in the 

 usual position in XI with its base close to the ventral surface of X/XI. 

 Its length is about one and one half times greater than its diameter. 

 It is slightly bent, and in the majority of the specimens examined it 

 was bent in such a way that the anterior end was directed dorsad or 

 laterad. The collar is distinctly set off from the body of the funnel 

 by a constriction. The diameter is only about one half that of the 

 funnel. The free margin of the collar is not reflected but projects 

 towards the developing sperm mass. The sperm duct is confined to 

 XII. It seems to be much shorter than is usual in other species. In- 

 stead of the mass of convolutions generally present in XII there are 

 at most but three or four coils, and from these the duct extends di- 

 rectly to the penial bulb. 



Penial Bulb. — In structure the penial bulb (PI. X, Fig. 32) con- 

 forms to the lumbricillid type as defined by Eisen. It is well devel- 

 oped, and is conspicuous in transverse sections of the body through 

 XII. It is completely invested by a strong musculature which ulti- 

 mately connects with the muscle layer of the body wall. When the 

 bulb is completely retracted the penial invagination is large, having a 

 depth equal to the length of the bulb. The sperm duct meets the bulb 

 on the dorso-ectal surface and pentrates it for a short distance. Within 

 the bulb it is replaced by the penial lumen which, curving broadly 

 laterad, extends to the penial invagination, opening into the latter 

 about midway of its depth. The cuticula lines the invagination and 

 also extends into the penial lumen as a lining. The bulb is composed 

 of two groups of cells. One group occupies the dorsal part of the 

 organ, and is composed of cells which occur near the periphery but 



