106 



DR. C. L. BOULENGER 01^ 



and come to occupy a dorsal position between or above the uterine 

 caeca. 



The testicular follicles are in some cases enclosed in small 

 cavities which, in agreement with most recent workers, I consider 

 to be coelomic ; these cavities are in places considerably enlarged, 

 and are then filled with large masses of mature spermatozoa 

 (PI. YII. fig. 5) ; their size equals or exceeds that of the uterine 

 spaces, which they resemble except for the nature of their contents. 

 Some of these cavities seem to have lost their communications 

 with the rest of the male organs, and I am at a loss to explain 

 how the spermatozoa/ within them can make their way to the 

 exterior. 



Wheeler seems to have observed a somewhat similar condition 

 of the male organs in his species M. circinatum, but in this form 

 vesiculse seminales and " penes " appear to be absent ; in M. cross- 

 landi the majority of the testicular folliclescommunicate with the 

 vasa deferentia, and through these with seminal vesicles which 

 open on to the short male papilla?. 



Female Organs. 



The female organs of M. crosslandi are very similar to those 

 just described by me in M. costaium. The single pair of hollow 

 ovaries (PI. YIL fig. 1) lies ventro-laterally to the stomach just 

 behind the point of origin of the first pair of intestinal trunks. 

 The cavities of the ovaries communicate with a pair of narrow 

 coelomic tracts which run upwards along the sides of the stomach 

 to join the small median coelomic space from which the uterine 

 branches are given ofi:". The latter are numerous and relatively 

 very slender ; they follow the main ramifications of the intestine. 



As in M. Gostatum, the oviduct communicates with the median 

 uterine ccelom by means of a narrow ciliated duct, which in this 

 species is rather long. The oviduct itself is very slender and 

 much compressed so as to appear crescentic in transverse sections; 

 it decreases in width considerably in the region of the rectum 

 and opens on the cloacal papilla by a very narrow terminal tube. 



N^ephridia. 



The nephridiff (PI. VII. figs, 2-5) occupy very much the sam^ 

 position as in M. cosdatwrn^ and, as in that species, open posteriorly 

 into the sides of the rectum close behind the commencement of 

 that organ. Unlike M. costatum, the anterior ends of the nephridia 

 do not communicate directly with the median uterine coelom, but 

 open separately into the narrow anterior end of the oviduct, so that 

 the three tubes whicb. afford communication between the ccelom 

 and the exterior possess but a single internal opening. 



The anterior terminal part of each nephridium has the form of 

 a transversely set narrow tube lined with long cilia ; this widens 

 out laterally when the organ follows a I'ather sinuous course, 

 backwards and downwards, and comes to form a broader tube 



