LOPHOMEMA SPIRALIS. 131 



supplies the gonad in the usual way and in the head region breaks up into a 

 system of sinuses that become continuous witii the blood spaces lying at the 

 sides and beneath the intestine. In the region of the accessory reproductive 

 organs the lacunae become very circumscribed, but ,so far as they have been 

 traced they exhibit essentially the same relations as in P. hmvaiiensis. The 

 corpuscles of this species (Plate 36, fig. 14) exhibit no features worthy of note. 



The paired gonad extends forward to a point some distance behind the 

 junction of- the pharynx and stomach-intestine. Posteriorly it ends abruptly 

 slightly in front of the j)ericardium with which it is connected by two short 

 ducts. The arrangement of ova and sperms are the same as in the foregoing 

 species. From the posterior end of the pericardial cavity the coelomoducts 

 arise and proceeding forward (Plate 8, fig. G, and Plate 9, fig. 5) almost hori- 

 zontally unite with the shell gland. In one specimen the first section of these 

 tubes is of small diameter and ill defined, while in the other it is well developed 

 and is filled with spermatozoa that also crowd the pericardium. In this same 

 individual there is a circumscribed area including the extreme posterior tip of the 

 pericardial cavity and the neighboring section of the coelomoduct where muii- 

 bers of spermatozoa are attached to the epithelial lining. Beyond this jioint 

 for some distance the duct continues of small calibre, with an epithelial lining 

 composed chiefly of goblet-shaped cells charged with a clear secretion, and then 

 suddenly terminates in a bulb-like enlargement that in turn luiites with tlie 

 seminal receptacle and the slime gland proper. At first the cells in this swollen 

 division are of greater height and more slender than those atljacent, and attach 

 vast numbers of spermatozoa, l:)ut more anteriorly sex cells are lacking and the 

 epithelium consists of goblet-shaped elements like those just descril^ed save that 

 they are of larger size. The same type of cell also occurs in the elongated seminal 

 receptacle except at its distal end where the cells are lower, more compact and 

 also attach large numbers of spermatozoa. 



The ventral limbs of each coelomoduct extend backward from the point 

 of attachment of the seminal receptacle to a point a short distance in front of 

 the cloaca where they unite and communicate with the exterior by a single 

 opening. The epithelial lining in this part of the duct is relatively very high 

 and gives evidence of forming two distinct secretions. The cells in the anterior 

 third of the canal are much vacuolated and contain a small amount of some 

 faintly staining secretion. More posteriorly they gradually shade into more 

 slender and elevated elements that, in the posterior half of the cloacal passage, 

 contain numerous granules densely crowded in their distal portions. Such 



