62 EISEN 



by me such sperm-sacs are present, but vary greatly in size. In 

 Enchytrceus saxicola they are enormously large, extending as far for- 

 ward as the spermathecae. There are, however, no trabecula, at least 

 not in the species which were sectioned. Michaelsen mentions the 

 presence of sperm-sacs in Enchytrceus mcebii (4) , but does not use 

 their presence as a generic characteristic. 



Another characteristic relates to the transformation of the penial bulb 

 into separate papillae surrounding the lower part of the sperm-duct. 

 Such papillae are found in all other Enchytraeid genera which I have 

 investigated, or which I have seen illustrated. In Enchytrceus the 

 spermducts open independently of any glands. There are however 

 glandular complex in the vicinity of the spermiducal pores in several 

 of the species, and perhaps in all, but they are situated some little 

 distance from the lower part of the sperm-duct, or if close, are still 

 distinctly separated from them. At any rate the sperm -ducts are never 

 directly connected with any glands or ducts of glands, but open inde- 

 pendently of any accessory structures through the body- wall. 



DETAILED DESCRIPTION. 



Brain. The brain in Enchytrceus is characterized by the circular 

 mass of fibers in the posterior part of the fiber belt in the brain. As 

 this structure has not been studied in detail its nature is not understood. 



Nephridia. Characterized by the small anteseptal which consists 

 merely of the nephrostome. A similar arrangement is found in 

 Lumbricillus. In no instance is there an anteseptal resembling that 

 found in Fridericia. 



Penial papillce and structures. No penial bulb similar to the 

 one found in Fridericia, Lumbricillus, etc. The sperm-ducts always 

 open separately from the glandular masses, which are found in the 

 vicinity of the ducts. These glands are never surrounded by a special 

 muscular covering, but seem to be more intimately connected with the 

 epidermis, and as such covered by the general muscular layers of the 

 body. In some species we meet with a great number of slightly sepa- 

 rated glandular cushions, each consisting of many glandular cells 

 arranged in a pinnate or feathery manner, but all these cells open some 

 little distance from the sperm-ducts. In other species there are only a 

 very few such cell agglomerations. Now and then a muscular strand 

 may be seen to penetrate between the cells down to the body-wall. 

 The muscular penial bulb in other genera is in Enchytrceus separated 

 by a number of isolated muscular strands, which connect the body-wall 

 in the vicinity of the penial pore with the parietes higher up along the 

 sides of the body. 



