PRONEOMENIA ACUMINATA. 221 



testis a small duct arises from the dorsal side and coursing ventrally to a slight 

 degree it then pursues a direct path (about once again as long as is represented 

 in Plate 5, fig. 5) to the forward end of the pericardium. The lateral walls of 

 these small canals are folded to a slight degree, and the slender cells support 

 a ciUated coat. Toward the mid line the walls are relatively smooth and serve 

 for the attachment of small numbers of spermatozoa that have also made their 

 way into the front end of the pericardium. 



Posteriorly the walls of the pericardium are continuous with the coelomo- 

 ducts that arise as slender tubes with plain walls consisting of cubical, ciliated 

 cells. During the first part of their course each is crowded between the shell 

 gland and the somatic musculature, but after extending upwards of one third 

 the distance to their anterior attachment they shift into the angle between the 

 shell gland and the seminal receptacle and become considerably enlarged. The 

 walls show sUght signs of glandular activity and here and there the cells form 

 slight folds. The opening into the shell gland is borne on the summit of a 

 hemispherical papilla, and is further marked by a yellowish secretion (unstained 

 in haematoxyUn) that has escaped from the dorsal section and may be traced 

 ^me distance posteriorly in the lumen of the shell gland. 



Each seminal receptacle is an elongated sac, of sinuous outline when viewed 

 dorsally, resting upon the anterior horn of the shell gland. The walls are rela- 

 tively thick with sUght folds here and there and present a dense appearance 

 due apparently to the presence of a finely granular secretion. A very few 

 spermatozoa find attachment to the walls. The union with the shell gland is 

 made by means of a very slender, short tube placed sUghtly in front of the union 

 of the dorsal and ventral sections of the coelomoduct. 



The shell gland, or ventral division of the coelomoduct, is of the usual 

 horseshoe-shape, and as may be seen in the figures is a massive affair. For a 

 distance equal to half the length of the seminal receptacle its epithelial fining 

 is charged with a darkly staining granular secretion that in many places has 

 escaped into the adjacent relatively large Imnen. Posterior to this point the 

 nature of the cells changes abruptly for not only do they become of greater 

 height but the secretion, practically unaffected by haematoxyUn, acts as though 

 in fife it had been of a highly viscous character. This is especially true of the 

 elements of the ventral half of the organ which continue to present this appear- 

 ance throughout the median, undi\'ided section of the shell gland as far as the 

 point where it narrows to form the small, non-glandular tube communicating 

 with the cloacal chamber. On the other hand the dorsal cells of the median 



