1883.] Contributions to tlie Anatomy of the Hirudinea. 357 



has become lost, and the whole has become a many-lobed, ciliated, 

 spongy mass. 



Following upon the neck of the funnel is a dilatation into which 

 blood corpuscles are carried by the ciliary current. In Hirudo and 

 its allies the ciliated mass above described comes to surround this. 

 The position of this funnel varies :— 



in Clejosine it opens into the ventral sinus ; 

 in Pontobdella into special perinephrostomatous sinuses ; 

 in Hiruclo and Aidostoma into remnants of a chcumtesticular 

 sinus ; 



in Nejphelis and Trocheta into botrjoidal spaces (pseudoccelom). 



The portion of the gland which follows upon the funnel exhibits a 

 degenerate condition ; this is probably to be accounted for by the fact 

 that the funnel is gradually losing physiological importance, its 

 function in regard to the secretion of nitrogenous waste being taken 

 on by the blood-vessels. Those genera in which the funnel remains 

 best developed exhibit but little capillary development, and vice versa. 



Following upon the degenerate portion or testis lobe is a portion 

 with numerous cells containing branched ductules ; these collect 

 together and a central duct is formed, which after a long and winding 

 course either opens directly to the exterior (Clepsine), or into a space 

 which then opens to the exterior. 



The lumen is throughout intracellular in origin. 



This description, excepting as regards the funnel, does not apply to 

 Pontobdella or Piscicola. 



The author describes as existing there a most curious network of 

 tubules, apparently continuous throughout the body and not seg- 

 mented. These tubules are exceedingly small, and their continuity 

 is a very difficult point to determine with certainty. 



These tubules are arranged very irregularly, they turn, twist, bend 

 upon themselves, and anastomose with one another in a most elaborate 

 manner. Their walls become very thin at parts, but never present 

 any opening. The walls present a rod-like structure, such as exists in 

 the nephridial cells in other genera. The lumen is intracellular, the 

 cells being much branched and very large. 



The author has been unable to trace their connexion with the 

 funnels, or with a series of very rudimentary vesicles, but such a con- 

 nexion probably exists. The author has also been unable, owing doubt- 

 less to the roughness of the skin, to see the external apertures ; he has, 

 however, seen them in Piscicola, where a similar structure obtains. 



The author proposes to reserve any general conclusions as to the 

 systematic position of the Hirudinea which may be drawn from these 

 facts for another communication. 



