STRUCTURE OP EARTHWORM ALLIED TO NEMERTODRILUS. 585 



segment ; the intestine which immediately follows has at first 

 three typhlosolar folds ; later on the two lateral and shorter 

 folds disappear. The ventral wall of the pharynx is con- 

 nected with the uephridial tubes of its segments ; they open 

 into the interior of the pharynx. 



(5) The area surrounding the setse of each side of the body 

 is shut off from the general body-cavity, forming a paired 

 series of chambers ; in the oesophageal region is developed a 

 perihsemal coelomic space surrounding the suboesophageal 

 vessels. 



EXPLANATION OF PLATES XXXVIII & XXXIX, 



Illustrating Mr. Frank E. Beddard^s paper ''On the Structure 

 of an Earthworm allied to Nemertodrilus, Mich., with 

 Observations on the Post-embryonic Development of 

 Certain Organs." 



Anatomy or Libyodrilus violaceus, Nov. Gen., N. Sp. 



Fig. 1. — Dissection to show the principal organs, i. Testes. Sp. s. Sperm- 

 sacs, od. Oviduct. V. d. Vasa deferentia. at. Atrium. S. Spermathecal 

 sac. g. Gizzard. 



Fig. 2. — Ventral surface of Segments 13 — 18. sp. Spermathecal pore. 

 $. Oviducal pores. ($. Male pore. 



Fig. 3. — Fragment of cubicle, showing nephridial pores {n.). 



Figs. 4, 5, and 6. — Three figures drawn from a continuous series of sec- 

 tions, and illustrating the development of the spermathecal sac. Spt. Septum 

 separating Segments 12, 13. S. Hinder wall of spermathecal sac, the cavity 

 of which is lettered *S^. sac. ov. Ovary. N. Nerve-cord. 



Fig. 7. — Longitudinal section through a portion of one of longitudinal 

 nephridial ducts, a. Branches given off from duct. JV. Junction with one 

 of paired uephridia. The thick gelatinous connective tissue in which the duct 

 is shown ; n. Nuclei of this tissue. 



Fig. 8. — Penial setae. 



Fig. 9. — Spermathecal sac and neighbouring organs. S. Sac. a. Diver- 

 ticula of the same. /•. o. Receptaculum ovorum. od. Oviduct, oss. CEsopha- 

 gus. n. Nerve-cord, 



Fig. 10. — Section through a portion of one of paired nephridia. a, b. Ne- 

 phridial tubes, n. Nucleus of same, c, c'. Peritoneal inyestment. 



) 



