AX AFRICAN MEDUSA. 



73 



much contracted, so that the largest specimens measured no more 

 than 6*5 mm. in diameter, exclusive of the tentacles. 



Umbrella. — In all the preserved specimens from the Norquane 

 River, the umbrella is disk-shaped and considerably flattened at 

 the top ; it is about 3| times as broad as high. 



Manubrium and Mouth. — The manubrium is also much con- 

 tracted in all the individuals, and the mouth appears as a wide 

 circular aperture. Observations on the living animal showed, 

 however, that the mouth could be completely closed. In this 

 connection it will be recalled that one of the Zambesi specimens 

 of L. rhodesice was described as possessing an almost conical 

 manubrium and a nearly completely closed mouth. Gravely and 

 Agharkar (16) have shown that L. indica is also capable of 

 closing the mouth, small specimens doing so more frequently 

 than large ones. 



Gonads. — The gonads are poorly developed in all the indi- 

 viduals ; so far as could be ascertained the majority belong to 

 the male sex. The Nonpiane specimens were collected about the 

 same time of the year as the originally described specimens of 

 L. rhodesice ; these also had the gonads poorly developed except 

 in one insta,nce, where a fairly well-formed ovary occurred. 



Text- figure 1. 



Longitudinal horizontal section through part of the nettle-ring of Limnoenida 



rhodesice, X ahout 150. 



c.c, circular canal; end., endoderm ; n.r., nettle-ring ; Tr., parasitic 



TricAodina. 



Tentacles. — In structure and arrangement the tentacles are 

 precisely similar to those of the Zambesi specimens. The number 

 of these organs varied in the different individuals from about 85 

 to 110; owing to the state of contraction of the umbrella-edge 

 they appear very closely crowded together, and are therefore 

 somewhat difficult to count with any accuracy. As in the other 

 species the tentacles are arranged in series, according to size — 

 the perradial, interradial, and adradial being the largest. The 

 larger tentacles have long narrow bases attached to the exumbrella 

 surface of the bell and devoid of nematocyst batteries ; the 

 smaller ones are more cylindrical in shape and are only attached 



