ENCHYTR^EID^E 



the equatorial of the atrium. The most characteristic part of the 

 efferent apparatus is the large accessory gland already described. 

 This gland, which consists as usual of a complex system of unicellular 

 glands, opens by a large and prominent duct into a special penis, 

 which projects far outside the spermiducal pore. In pi. iv, fig. 4, the 

 section of the body passes through the two accessory glands. The 

 atria and spermducts would be cut by sections posterior to this one. 

 The inner lumen of the at- 

 rium and the lower part of 

 the sperm-duct or penis 

 proper are lined by large 

 cubical cells, between which 

 the narrow ducts of the 

 atrial glands open. The 

 penial bulb contains a num- 

 ber of the usual glands, sep- 

 arated by muscular fibers and 

 connective tissue. In diam- 

 eter these glandular masses 

 are about equal to the diam- 

 eter of the atrium. 



Nephridia. These or- 

 gans are thick and the ducts 

 could not be properly fol- 

 lowed. Figure lib repre- 

 sents the average form. 



Spermatophores (figures 

 in text). In my earliest 

 paper on Enchytrseidae (Ei- 

 sen, 13) I gave it as a char- 

 acteristic of Mesenchytrceus / 



that the spermatozoa were 



. , * ., j FIG. n. Mesenchytrceus franciscanus. 



encysted when they entered 



the sperm-funnels. This was found to be the case in all the three species 

 described at that time. In the majority of species of this genus no 

 similar structures have been seen, though Michaelsen has mentioned 

 them (Michaelsen, 4, p. 32) as existing in M. beumeri. In some ten 

 or more species of this genus so far investigated by myself, no encysted 

 spermatozoa have been found, but in M. franciscanus we find them 

 present in large numbers. As Michaelsen has stated, the testes seem 

 to break up in smaller parts. These smaller parts consist, in M.fran- 



