y6 EISEN 



Penial bulb. The penial bulb in Lumbricillus differs in structure 

 from that of Mesenchytrceus and Enchytrceus, but resembles that 

 found in the other genera so far as known. The bulb consists of an 

 exterior capsule of muscle strands. Inside the capsule we find one 

 or more kinds of glands, which radiate from the base of the bulb 

 towards the periphery. These glands are all single cells, each one of 

 which is separate from those nearest, each one opening separately 

 around the penial pore. Some species possess glands which open 

 in the lower part of the sperm-duct, inside the bulb and close to 

 the pore (pi. xin, fig. i). It is probable that this latter structure 

 may be found in all the species, and that it is characteristic of the 

 genus. 



Sperm-sacs and testes. As has been already stated in a previous 

 paper (Eisen 1900), each separate lobe of the testes is capped by a 

 small sperm-sac. This arrangement is also found in Ocnerodrilus 

 occidentalis^ but not in the other species of Ocnerodrilus, which 

 led me to separate O. occidentalis as a special subgenus. The testes 

 in the various species differ from each other to some extent, but not 

 sufficiently to furnish species characteristics of any practical use. 

 The spermatogonia of the testes separate and fall into the small 

 sperm-sacs and there undergo their further development into sperma- 

 tozoa. Spermatophores are not known in this genus. 



SYNOPSIS OF SPECIES OF LUMBRICILLUS DESCRIBED IN THIS PAPER. 



I. SPERMATHKCA WITH A SINGLE ROSETTE OF GLANDULAR CELLS AT BASE. 



These cells do not extend upward on the stalk or on the main part of the 

 spermatheca, but enter the lower part of the spermatheca about ten to fifteen 

 cells high. 



The lower half of the spermatheca enlarged and pouch-shaped. Ventral glands 

 in XIV and XV, ventral and slightly lateral i. L. santceclarce sp. nov. 



II. SPERMATHECA COVERED WITH GLANDS ALONG THE ENTIRE LENGTH OF THE 



DUCT, BESIDES POSSESSING A ROSETTE OF GLANDS AT THE BASE. 



Brain distinctly emarginate posteriorly. Spermatheca with a distinct narrow 

 duct uniting the ampulla with the pore. Glands covering the duct increas- 

 ing in length toward the base. Ventral glands in XIV, XV, XVI, and XVII, 

 the glands of equal size 2. L. merriamisp. nov. 



Brain truncate posteriorly. Spermathecal duct long, but the ampulla very 

 small and hardly differentiated exteriorly. Ventral glands of large size in 

 XIV, XV, XVI, XVII, XVIII and XIX 3. L. annulatus sp. nov. 



Brain emarginated posteriorly. Spermathecal ampulla large, with a distinct 

 duct leading to the pore. Glands covering the duct of even size, not broader 

 toward the base. Ventral glands in XIII, XIV, XV, XVI, and XVII. 

 Nephridia with glandular zone near the nephrostome...4. L. ritteri sp. nov. 



III. SPERMATHECA WITHOUT DISTINCT GLANDULAR COLLAR AT BASE, but with 

 a continuous covering of glands from top of duct to base, the glands gradu- 

 ally increasing in size toward the base. 



Spermathecal ampulla globular. Ventral glands in XIV, XV, and XVI, in- 

 creasing in size posteriorly ; ventral, lateral, and dorsal. 



5. L. franciscanus sp. nov. 



