STRUCTURE OP EARTHWORM ALLIED TO NEMERTODRILUS. 539 



On the Structure of an Earthworm allied to 

 Nemertodrilus, Mich., with Observations 

 on the Post " embryonic Development of 

 Certain Organs. 



By 



Frank E. Beddard, IH.A., 



Prosector of the Zoological Society of London, Lecturer ou Biology at 

 Guy's Hospital. 



With Plates XXXVIII and XXXIX. 



Table of Contents. 



I. Introductory, p. 539. 



II. List of Memoirs consulted, p. 

 541. 



III. External Characters, p. 542. 



IV. Anatomy and Histology, p. 544. 



V. Description of some Young 

 Stages, p. 572. 



VI. Homologies of the Reproduc- 

 tive Organs in Eudrilidse, p. 

 579. 

 VII. Definition of Genus Libyo- 

 drilus and Species L. vio- 

 laceus, p. 583. 

 VIII. Summary, p. 583. 

 IX. Explanation of Plates, p. 585. 



I. Introductory. 

 The investigations of Rosa (5),^ Michaelsen (3, 4), and more 

 recently of myself (1), have shown that the earthworm fauna of 

 tropical Africa is characterised by an extraordinary abundance 

 and diversity of types of the family Eudrilidse. This family 

 had been known for a long time by the genus Eudrilus alone, 

 which seemed to occupy — principally on account of the struc- 

 ture of the reproductive system— a somewhat isolated position 

 among the Oligocha^ta. 



1 The numbers in brackets refer to the list of papers on p. 541. 



