No. 3.] 



SPERM A rOPHORES. 



383 



examine briefly the form, structure, and contents of the male 

 efferent ducts. A glance at Fig. 5 will show that these ducts 

 are differentiated into a number of different regions, each of 

 which seems to have a special function. Beginning with the pore, 

 which lies between the tenth and the eleventh ganglia, we find a 

 very short median tube, which bifurcates beneath the ventral 

 cord, giving rise to two diverging horns {s), which are continued 

 into a convoluted tube (ze/, g, d) of nearly uniform, but much 

 smaller, diameter ; then follows an enlarged sigmoid coil {vs), and 

 finally the long narrow tube {vdc), which receives the six short 

 testicular ducts {vd). The sigmoid portion is a thin-walled 

 reservoir completely filled with sperm-bundles, fulfilling the 



.m 



Fig. I. — Section from the posterior half of the ductus ejaculatorius, showing 

 bundles of spermatozoa {sp) massed together, and a few granular corpuscles {gc), 

 probably secretions from the anterior, glandular half of the duct. The muscular 

 layer (w) is strongly developed, and the large lumen is lined with a thin epithe- 

 lium {ep'). 



office of a vesicuta seminalis. The convoluted portion con- 

 necting the vesicula seminalis with the terminal horn-like 

 enlargement {s) appears externally to be a nearly uniform tube, 

 and ^s usually called the ductus ejaculatorius (d). But an exam- 

 ination of the structure and contents of this portion reveals the 

 fact that it is really differentiated into two parts which fulfil 

 different functions. The posterior half (d) has a thicker mus- 

 cular wall, and a much larger lumen than the anterior half 

 (za and g) ; it is lined with a thin epithelium, and is filled with 

 spermatozoa. In the anterior half this epithelial lining takes 

 the form of long columnar gland-cells, radially disposed, with the 



