238 KINORHYNCHA 



pharynx and stomach. From two to eight eye-spots have been 

 described by earlier writers, but Eeinhard was unable to find 

 them in the (distinct) species which he principally worked at, 

 though he noted their existence in the solitary specimen of the 

 original species, E. dujardini, which he obtained. 



Reproductive Organs. The sexes are distinct. The repro- 

 ductive glands form a pair of tubular sacs, opening ventrally on 

 either side of the anus, and extending forwards beside the gut as 

 far forwards as the fifth to the second segment in the male, but 

 only to the fourth at furthest in the female. The ova are large 

 nucleated cells embedded in the protoplasmic lining of the 

 ovarian sac, and acquiring a distinct shell as they approach its 

 opening. Three-quarters of the testis sac is occupied with 

 granular protoplasm containing a quantity of small nuclei ; the 

 lower part alone contains mature spermatozoa. Adjoining each 

 external opening in the male ae a pair of short hollowed spines, 

 which may perhaps serve as organs of copulation ; but nothing 

 is really known of this process or of the development of the egg. 

 It is almost certain, from the absence of developing eggs within 

 Echinoderes, that the genus is not viviparous. 



From the foregoing description it is obvious that Echinoderes 

 approaches the Nematoda very closely : the two main points of 

 difference are its ciliated kidneys and its bilaterally paired sexual 

 organs. Possibly the study of such forms as Desmoscolex (Fig. 

 81, p. 159) may reveal closer affinities. 



