514 



MEDUSiE OF THE WORLD. 



bell-margin. In Chlropsalmus, on the other hand, each of the 4 pedalia gives rise to side 

 branches which bear tentacles. Moreover, in TripeJalia there are no subumbrella, liernia- 

 like, gastric diverticula as in Chiropsalmtis. 



Tripedalia cystophora Conant. 



TrlprJalia cyslophora, Conant, 1897, Johns Hopkins Univ. Circulars, No. 132, p. 9, fig. 9; 1898, Mem. Johns Hopkins Univ. 

 Biol.Lab., V0I.4, No. 1, pp. 5, 22; figs. 17-30, plates i, 2, 5, 7, figs. 44, 45, 53-56, 68, 71. 



Bell cubical, with edges slightly rounded; 12 mm. high, and ot aiiouf 15 mm. wide. 

 There are 4 interradial groups of pedalia, each group consisting of 3 distinct, separate pedalia, 

 each one of which arises from the bell-margin and gives rise to a single tentacle. The pedalia 



are flattened and resemble a slender knife-blade, and 

 are about half as long as the bell-height. The 12 

 tentacles are each about 2.5 times as long as the 

 pedalia. 4 sense-clubs are situated in niches at about 

 one-fifth or one-fourth the height of bell above mar- 

 gin. Each sense-club has 2 large, median and 4 small, 

 lateral e\es and a terminal lithocyst. The median 

 e\es have doubly convex lenses. Velarium about 

 one-sixth as broad as bell-diameter. There are 24 

 simple, unforked velar canals, 6 in each cjuadrant. 

 These velar canals are triangular in outline, and the 

 8 adjacent to the 4 frenulae are only half as wide as 

 the others. Stomach wide and shallow, but tbethroat- 

 tube is long and extends downward in some cases to 

 bell-margin; cruciform in cross-section, with 4 well- 

 developed, oral lobes in the radii of the sense-organs. 

 There are 15 to 21 organs, resembling lithocvsts, in 

 the gelatinous walls of the manubrium; each con- 

 sists of a round or oval sac lined with ciliated cells 

 which keep in motion and bear up an irregular, 



Fig. -330. — Triptdalia cystophora. i , j - t^, 



'' '^ ' '^ coarsely granulated concretion. 1 nese organs are 



scattered irregularly through the gelatinous substance and are probabl)' of entoderinal origin. 

 The small, tapering, gastric cirri are brush-shaped and spring from 4 short stalks in the inter- 

 radial corners of the stomach. There are 4 wide, perradiallv situated, gastrovascular 

 pouches in the umbrella, which are separated by 4 interradial septa; but these septa are 

 mcomplete in the regions ot the pedalia, and thus the 4 stomach-pouches are placed in com- 

 munication one with another, as in other CharvbdeidcC. The gonads are 8 leaf-like sheets 

 attached to the sides of the 4 interradial septa and projecting out into the 4 perradial 

 stomach-pouches. The medusa is light )cllowish-brown, the gonads being of the same color. 



Figure 330 shows a mature female, 4 times natural siz.c, drawn from nature, by the author. 

 In order to illustrate their shape, the lips are shown twisted 45° from their natural position. 



This species is found in Kingston Harbor, Jamaica, in great abundance during the sum- 

 mer among the mangrove roots of the islands in a shallow, muddv lagoon on the western side 

 of the harbor, north of Port Henderson. It disappears in winter. 



The dimensions of the mature specimen here figured are as follows: Bell 12 high, 15 

 mm. wide. Pedalia 5 mm. long, 2.1 mm. wide. Rhopalia 2.25 mm. above velarium margin. 

 Stomach 5.5 mm. wide, 7 mm. long. The gonads were mature and the gastrovascular space 

 filled with swimming planulae. This medusa was captured on Ma\' 24, igog. 



Conant succeeded in obtaining females having embryos within their gastrovascular 

 pouches. The embryos were thrown out into the water as free-swinimiiig planuhe, which 

 settled down on the bottom and sides of the aquarium in a day or two and (juickly developed 

 into small Scyphostomae with mouth and typically with 4 tentacles and 4 taeniolse, although 

 3 and 5 tentacled specimens were not uncommon. In this condition they lived for 3 weeks 

 without essential change. I find that man)-, but not all of the planul.x, are besprinkled with 

 dark brown pigment-spots which are scattered over the ectoderm of the narrow posterior end 

 of the larva. 



