IQ EISEN 



sperm-duct instead of in the duct itself. In the genus Mesenchytrceus 

 these glands are found only in few species, while in Lumbricillinse 

 they are found in all species examined by me. 



The various glands of the spermiducal apparatus . In the fore- 

 going as well as in the following paragraphs the various glands of the 

 spermiducal apparatus have often been referred to in their respec- 

 tive places. As their number is considerable and as their structure is 

 somewhat complicated I will here summarize their most important 

 characteristics and endeavor to classify them according to their nature 

 and location. There are at least five different kinds of glands opening 

 into or in the proximity of the sperm-duct. 



The first group of glands are those which open in the sperm-duct 

 exterior to the penial bulb. These are the atrial glands which, as we 

 have seen, may directly penetrate between the atrial inner epithelium 

 and open into the atrial chamber and pour their secretions there. Or 

 they may follow between the atrial epithelium and the atrial muscular 

 layers and empty their contents around the penial pore. An illustration 

 of the former is seen in Mesenchytrceus maculatus (pi. v, fig. 5). 

 The latter is illustrated in Mesenchytrceus grandis (pi. vn, fig. 2) . 



Another group of glands in the lowest part of the sperm-duct, or 

 more particularly in the short extension of the sperm-duct, is found in 

 many species of Lumbricillinae and in some species of Mesenchytrceus 

 for which see pi. xi, fig. 4 {Mesenchytrceus asiaticus), and pi. xv, 

 fig. 7 {Henlea guatemalce) . Such glands I have referred to as ' intra- 

 penial glands.' 



Another group of glands are designated ' copulatory glands.' These 

 glands are found inside the penial bulb, but do not open into the sperm- 

 duct, but around the spermiducal pore, on the body surface of the 

 penial bulb. Such glands are seen in pi. xi, fig. 4 {Mesenchytrceus 

 asiaticus), and in pi. xvm, fig. i {Lumbricillus annulatus*). 



The copulatory glands may open separately, as in pi. xiv, fig. i 

 {Marionina americana), or they may open in fascicles in separate 

 pores, as in pi. xv, fig. 6 {Henlea ehrhorni}. The two kinds of 

 glands may be found in the same penial bulb, and their arrangement 

 and occurrence are probably characteristic of the species. 



The fourth class of glands is the accessory glands which open out- 

 side of the penial bulb, as illustrated in pi. ix, figs. 5, 6 {Mesenchy- 

 trceus pedatus) . 



Anc her set of glands are those found in Enchytrceus, which open 

 in grouj. outside of the penial pore (pi. xix, figs, i and 6). 



