HYDROMEDUSAE. 741 



octant: 9, 10, 9, 9, 10, 9, 9, 9). Sense organs, 14 (the following numbers in each octant: 

 1, 1, 2, 2, 3, 1, 2, 2). In this specimen the gonads vary very much in size. Two pairs, 

 male and female, oppositely situated and fully developed, are large ; the other two pairs are 

 very small. 



Vanhoffen's figures show that the gonads are very unequal in size. Four are large 

 and four are very small, looking as if they were just beginning to develop. The large and 

 small gonads occur on alternating radial canals. Vanhoffen does not state the sex of the 

 gonads, but the largest look immature in his figure. In the smallest Maldive specimen, much 

 younger than Vanhoffen's specimens, the gonads are just beginning to develop. They vary 

 slightly in size, showing that they have not all started to develop at the same time, but 

 the sizes are not arranged in any definite order. In the second specimen the gonads are 

 all about the same size and shape, but not quite fully developed. In the largest specimen 

 there is a well-marked difference in the size of the gonads, which are arranged in pairs, 

 male and female, two large and two small, so that the large and small are not upon alternating 

 canals. The male and female gonads are always upon alternating canals, but in these specimens 

 there is no evidence to show that one sex is in advance of the other, though the gonads are 

 not all of a size. 



The occurrence of both male and female gonads upon the same individual is the most 

 interesting character of this species, for, so far as I know, hermaphroditism has not been 

 hitherto recorded for any Craspedote medusa. 



Order Narcomedu.sae. 



Family Aeg^inidae, Gegenbaur, 1856. 



Genus Svlmundella, Haeckel, 1879. 



Generic Character. Aeginidae with two tentacles and with a stomach having eight 

 pouches. 



Solmundella bitentaculata (Quoy et Gaimard) 1833. (PI. LVI. fig. 3.) 



Charybdea bitentaculata, Quoy et Gaimard (1833, Tom. iv. p. 295, PI. xxv. figs. 4 — 5). 

 Aeginella bitentaculata, Haeckel (1879). 



Description. Umbrella somewhat cone-shaped, a little broader than high. Stomach circular, 

 nearly as wide as the umbrella, having lateral pouches about twice as broad as high, containing 

 the gonads. Four radial canals. Two opposite, non-contractile tentacles, which are situated 

 above the stomach and are about three times longer than the diameter of the umbrella. 

 Sixteen sense organs, each with a single otolith. 



Size. Umbrella 3^ mm. in width and about 3 mm. in height. 



Length of the tentacles about 6 — 10 mm. 



Distribution. Indian Ocean; Maldive Islands, Minikoi (Gardiner, 3 Aug. 1899). Austra- 

 lasian Seas ; Amboina Is. (Quoy et Gaimard). 



95—2 



