CLOACAL GLANDS OF MALE NECTURUS 453 



do not ])ranch, and end blindly. In fresh material they appear 

 opaque, while tubules of the cloacal gland usually appear clear. 

 The difference in appearance is due to the different character 

 of the secretion in their lumina. 



All of the tubules of the pelvic gland open into the dorsal 

 portion of the cloacal tube. They are arranged in four groups: 

 a small cephalic medial group of short tubules (fig. 10, plv.gl."); 

 further caudad, two symmetrical, lateral groups of somewhat 

 longer tubules (figs. 11, 12, plv.gl.'"), and a very large median 

 caudal group of long, greatly convoluted tubules (figs. 11, 12, 

 13, 14, plv.gl.'). The caudal portion constitutes the greater 

 part of the pelvic gland. The tubules which form the lateral 

 differentiations of the pelvic gland are comparatively few in 

 number. They are distributed cephalocaudally on either side 

 of the cloacal tube and lie close to the lateral septa {c.t.s.) which 

 separate the main mass of the pelvic gland from the more ven- 

 tral cloacal gland. 



The different groups of pelvic tubules are not distinctly sep- 

 arated from one another in anj- portion of the gland, but are 

 distinguished by the character of their glandular epithelium. 

 Owing to the great variety of secretory phases exhibited by the 

 different tubules, it is not always easy to determine with certainty 

 whether the tubules under consideration are of an entirely dif- 

 ferent character or are merely different phases of activity of 

 the same kind of tubule. It is with some hesitation, therefore, 

 that I have distinguished a median cephalic group, since cephalad 

 to the main mass of the caudal division of the pelvic gland the 

 tubules of its lateral differentiations approach the middorsal 

 line, and in serial sections are seen to be intermingled with the 

 more caudal tubules of the cephalic group. However, so far 

 as my histological study has progressed at this time, there ap- 

 pears to be good evidence that the tubules of the groups under 

 discussion, although intermingled where they come in contact, 

 possess secreting cells of two distinct types. The tubules of 

 the median caudal division, on the other hand, can be readily 

 recognized at all times. 



