355 



connection with the ciliated cups or funnels of the cloaca! pouches of 

 Echiuridae, has certainly no existence in Thalassema Neptuni. 

 I reserve a more detailed description of these organs for another 

 occasion. 



Genital Pouches. In Thalassema Neptuni there are two pairs 

 of genital pouches (anterior nephridia) which serve as reservoirs and 

 ducts for the generative products. In the month of March these pouches 

 were in an extremely reduced conditions in nearly all the specimens 

 examined. They consisted of very short reddish yellow bodies placed 

 in pairs behind the bases of the two setigerous sacs. They were in a 

 state of complete contraction so that no internal cavity could be seen. 

 At the base of each is a semicircular frill, covered with cilia and leading 

 to the internal opening of the sac. In this condition they resemble the 

 genital pouches of Echiurus as figured by Greeff (Plate I, Fig. 12 

 of his Monograph) . 



This semicircular frill is in certain species both of Thalassema and 

 of Echiurus greatly increased in size and its angles elongated and 

 twisted cork-screw-wise. 



In Echiurus unicinctus from Japan (collected by the , Challenger' 

 expedition) I find the twisted elongated condition of the frill which 

 leads to the inner orifice of the genital pouches. In Thalassema Moehii 

 Greeff has figured the elongated twisted condition of the frills of the 

 genital pouches (PI. VIII, Fig. 69) whilst in Thalassema Neptuni, which 

 I have studied in both the sexually ripe and the unripe condition, as also 

 in Echiurus Pallasii and Thalassema Baronii, in the specimens figured 

 by Greeff, they are not present; so that there appear to be some 

 species of Thalassema and some of Echiurus with a simple inner mouth 

 to the genital pouch, and some of each genus with a cork-screw-like 

 funnel. 



Although normally Thalassema Neptuni appears to be in a sexually 

 undeveloped state in the month of March, yet I found two specimens 

 amongst a hundred opened by me, in which the genital pouches were 

 distended with genital products. One of these was a male, and the 

 other was a female. The genital pouches in both cases were stretched 

 to such a degree that their walls were quite transparent and their vo- 

 lume immensely increased. Instead of being little sausage-shaped 

 bodies one twelfth of the length of the worm from mouth to anus, they 

 now extended over three fourths of the length of the body, and were 

 proportionately broad. 



In both male and female all four sacs were equally distended with 

 a white creamy substance, which on examination proved to be in the 



