46 



cates by a long, slightly crescentic slit. The forward portion (about one half of 

 the whole) of this gland is represented in text figure 1 4 , A and B. 



The sperm canal passes across the outer surface of the gland from above 

 downward and backward in the concavity which is readily seen in text figure 

 14, A, passing from right to left. (A small portion only of the sperm canal has 

 been modelled). The sperm canal is connected with the gland by a long, narrow, 

 slit-like lumen a portion of which is shown in the figures. The chief lumen 

 becomes larger toward the hind end of the gland and forms as a whole a deep 

 spoon-shaped cavity whose outer edge is connected with the sperm canal while 

 its other edges and both upper and lower surfaces communicate with numerous 

 flattened lumina. 



In the vertical section of the gland represented in text figure 14, B, it will 

 be seen that the majority of the lumina at the left of the chief lumen are 

 united by a common lumen which opens into the chief lumen a short distance 

 beyond the last section modelled. A simflar but smaller set of cavities is shown 

 in the upper right hand section of the photograph. These two systems are also 

 clearly shown upon the outer surface of the gland. Thus we see in the photo- 

 graphs, a large series of branching frond-like lumina opening into the forward 

 edge and partly into the inner edge of the chief lumen , and two similar but 

 smaller series which are converging to the upper and lower sides of the chief 

 lumen. The most marked flattening of the lumina and of the enclosing cellular 

 plates is in the longitudinal plane and I believe that the whole structure can be 

 correctly pictured if one imagines that an extensive elongation accompanies and 

 modifies the formation of a gland of the compound tubular type. A rapid elon- 

 gation of the canal at the time of the formation of the primary evagination 

 would draw it out into a long narrow pit and we will find that the prostata is 

 formed of a large series of such simple, or slightly branched pits. The elongation 

 would aff"ect the secondary evaginations in a less degrees and the tertiary evagi- 

 nations in a still smaller measure. But three primary evaginations of the seminal 

 vesicle would seem to be formed whereas in the prostata a large number have 

 been formed and are but slightly developed. 



The term "simple tabular gland" seems applicable to the type of structure 

 characteristic of the prostata. The nidamental and oviducal glands of the female 

 are of similar structure but in them the flattened pits are placed at right angles 

 to, instead of parallel to the main duct as in the prostata. The glands of the 

 seminal vesicle are twice or thrice compound tabular glands. 



The third portion of the seminal vesicle is a large tube into whose lumen 

 there projects from its outer and upper side a large, outwardly concave ridge 



