The South African Hirudinea. 309 



Whereas in other Glossiphoniidae the young attached to the 

 ventral surface are protected in a temporary " marsupium " formed 

 by the inflection of the lateral margins of the body, we find in this 

 new genus that the greater portion of the much thickened trunk 

 region is occupied by a large internal brood pouch, which displaces 

 the tissues of the body and has reduced the same to a remarkable 

 extent. This pouch opens to the exterior through a longitudinally 

 elongate aperture situated behind the centre of the ventral surface. 

 We may remark here preliminarily that this is the most extreme 

 and peculiar morphological development in the Glossiphoniidae. 



In this case dispersal over long distances is practically impos- 

 sible, since the accidental dropping of eggs from the ventral surface, 

 which might possibly happen in other forms, cannot take place in 

 Marsupiobdella. 



MAESUPIOBDELLA gen. nov. 



Glossiphoniidae of small size ; sensory annulus occupying the 

 middle region of the triannulate somite. 



Male genital pore opening to exterior between somites XL, xii, and 

 between post-oral annuli 21, 22. 



Female genital pore originally situated between annuli 2, 3 of 

 somite xii, but functionless in adult. 



Trunk portion of body greatly thickened, and containing a large 

 brood pouch which opens to the exterior on the ventral surface 

 through an elongate aperture. 



Somites v-xxvi triannulate ; xxvii biannulate. Eyes two. 



MARSUPIOBDELLA AFBICANA gen. et sp. nov. 



This interesting form was obtained in some abundance from the 

 surface of a fresh water crab by Dr. Purcell at Backen's Eiver, C.C. 



The specimens, which were preserved in spirit for some years, 

 show no pattern and have a homogeneous greenish-grey colour, 

 except that the head region and the posterior sucker have an opaque 

 white appearance. The head region shows an annulation which 

 is so faint and indistinct that it has been neglected in making a 

 count of the annuli on the dorsal surface. On the ventral surface 

 the two annuli immediately behind the anterior sucker have the 

 same white colouration, and are regarded as indicating the posterior 

 limits of the head region. The furrow separating these two annuli 

 is indicated on the dorsal surface of the head, and although distinct 

 it is so faint in comparison with the succeeding grooves separating 



