EISEN 



Clitellum. The clitellar cells small, narrow, and not prominent; 

 extend all around the body. The clitellar cells and the transverse 

 layer of muscles together equal in thickness the longitudinal layer of 

 muscles. All through the body the longitudinal layer is unusually 

 developed. Outside of the clitellum the epithelium and the transverse 



layer measure one unit each, while 

 the longitudinal layer alone measures 

 thirteen units. 



Spermathccce (fig. 14^). Only 

 one specimen dissected. Both sper- 

 matheca found to be of the same 

 size and form, and there is every 

 reason to believe the form constant, 

 and that the folding of the thick 

 part of the ampulla against the nar- 

 row part is characteristic of the spe- 

 cies. In one of the spermathecae 

 the apex of the ampulla is narrow 

 and cylindrical, while in the other 

 spermatheca the apex (from the place 

 marked with a -f) is thicker and ir- 

 regular. The folded parts of the 

 spermathecae were alike in both or- 

 gans. The ampulla extended back- 

 FIG. 14. Mesenchytrczus maculatus. ward to somite VI. I could not find 



any connection with the intestine. 



The diverticles equal in length the narrowest part of the duct. In 

 one specimen the narrow apical part of the ampulla was much longer 

 than in the other specimens, equalling in length the remainder of the 

 spermatheca. This is indicated by a dotted line in the figure (14 3) . 



Efferent apparatus. As only transverse sectioning was made the 

 relative proportions of the various organs could not be ascertained. 

 Funnels folded on themselves have a flaring lip. Diameter of the 

 sperm-duct equal to one unit, diameter of the atrium equal to three 

 units. Ducts relatively very narrow, confined to the clitellar somites, 

 in which they are considerably coiled. 



Atrial glands (pi. v, fig. 5). At least 12 atrial glands opening 

 into the atrium in the same horizontal plane, immediately outside of 

 the penial bulb ; all large, about three times the diameter of the atrium. 

 There may be a few more glands opening into the atrium at a lower 

 plane, immediately below the first one. The individual cells of these 



