1906.] TURBELLARIA OF THE CAPE VERDE ISLANDS. 709 



The eye-spots have the arrangement which is typical for the 

 genus. There are a pair of tentacle eye-groups, one on either side 

 of the brain, each consisting of four or five large eye-spots. In 

 front of these on either side are a very few (seven or eight) 

 smaller eyes. 



The musculature of the dorsal body-wall is unusually well 

 developed, especially the oblique inner layer. The dorsi-ventral 

 fibres also ai'e unusually abundant and of large size. 



The short blunt muscular penis projects downwards and a little 

 backwards into the antrum masculinum. It has no stylet. 

 From it the muscular ductus ejaculatorius runs forward, 

 rapidly widening to form a prostatic compartment whose walls are 

 lined with a secretory epithelium, but are not chambered. From 

 the anterior end of this chamber the duct runs forward again 

 as a narrow muscular tube, again soon widening to form a 

 vesicula seminalis, which receives at its anterior end the vasa 

 deferentia. The prostate and vesicle are not so clearly segmented 

 off from each other as in most species of Leptoplana ; in fact with 

 the conducting part they form a nearly straiglit tube whose walls, 

 surrounded throughout their entire length by circular muscle- 

 fibres, vary somewhat in thickness ; being thickest in those parts of 

 the tube v/here the lumen is greatest, that is to say in the prostate 

 and in the vesicula seminalis. 



The antrum femininum, opening close behind the antrum 

 mascidinum, passes dorsally into a narrow duct which receives the 

 secretions of the shell-glands, and then, turning backwards, opens 

 after a short course into a large accessory vesicle lined with a 

 vacuolated secretory epithelium. This vesicle contains in the 

 present specimen a quantity of spermatozoa. Just before it opens 

 into the accessory vesicle the vaginal duct is joined on its ventral 

 side by the common termination of the uteri. 



The shell-glands are very large, disposed in a dorsal and ventral 

 layer on either side of the middle line, converging on the sides of 

 the vagina. They extend outward to the margins of the body. 



Lp^jjtojjlcma graffii may be defined as a Leptoplana vnlh a very 

 elongated body. Penis vnthout a stylet ; prostate uncharahered,, 

 moderately dAstinct. Antrwni femininii/rii non-niuscida/r ; a large 

 spherical accessory vesicle present. 



Zygaxtroplana, gen. nov. 



Zygantroplana verrilli, sp. n. (Plate LII. figs. 1 & 2.) 



Two specimens. St, Yincent Harbour. (6.) 



" Amongst weed collected by a diver in 1 or 2 fathoms. 



•' Oval with a much waved margin. General colour brown, with 

 broad, nearly colourless margin, the edge itself with a light red- 

 brown tinge. Under side colourless." 



Length 7 mm. ; breadth 4 mm. 



The eye-spots are arranged in two rows convex inwards, lying 

 at the sides and in front of the level of the brain. This organ is 



