ON MONOFYLEPHORUS LIMOSUS. 41 



sequently well behind the middle .... the skin is devoid of 

 cnticular pilosities and perfectly smooth." " The setae are all of 

 the usual short, bifid, hooked form with a deeply cleft lip and the 

 terminal process somewhat longer and more slender than the widely 

 divergent basal one. . . . The pharyngeal region is very small, 

 though its glands extend diffusely to segment V or VI. ... In 

 young worms, in winch the transparent body wall permits the 

 nephridia to be readily studied, they are absent from many somites 

 and developed on one side only of others, but in full-grown worms 

 few segments, except at the posterior region, lack them. The funnel 

 is small, with the prolonged lip or tongue more slender and elongated 

 than in Monopylephorus pilosus. It passes into a short neck, which 

 penetrates the septum and joins an irregular massive region in which 

 the canal is much folded, with granular coalesced walls and irregular 

 lumen in the anterior part, while in the posterior part the lumen 

 becomes more regular and provided at intervals with ciliated 

 ampullae. From this portion an elongated lobe passes caudally and 

 medially along the ventral blood vessel. In this lobe are four canals 

 arranged in two loops, the proximal one of which contains ciliated 

 ampullae, while the distal one lacks cilia and, after returning to the 

 massive region, passes into a large thick-walled efferent canal, the 

 lumen of which exhibits a few irregular lateral diverticula, and 

 which finally opens to the exterior by a pore situated a short 

 distance anterior to the ventral setae bundles." " The external 

 opening of the genital bursa is a conspicuous median, transversely 

 elongated aperture in the setae zone on the venter of XI. The 

 female pores are paired in the furrow XI/XII, and the spermathecae 

 open close together in a common depression just behind furrow 

 IX/X." " The spermatozoa are never fashioned into spermatophores, 

 but fill the ampulla in compact masses and bundles." The above 

 quotations are from Moore. 



