F. S. CONANT ON THE CUBOMEDUS^E. 5 



Family III : TRIPEDALID^E (1897). 



Cubomedusse with four interradial groups of tentacles, each group 

 having three tentacles carried by three distinct pedalia ; without marginal 

 lobes in the velarium ; with sixteen marginal pockets ; without pocket 

 arms in the stomach pockets. 



Genus : Tripedalia. 



For the present the characteristics of family and genus must neces- 

 sarily be for the most part the same. The genus is distinguished by 

 having twelve tentacles in four interradial groups of three each ; velarium 

 suspended by four perradial f renula ; canals in the velarium ; stomach 

 projecting somewhat convexly into the bell cavity, with relatively well- 

 developed suspensoria ; four horizontal groups of gastric filaments, each 

 group brush-shaped, limited to the interradial corners of the stomach. 



Species: Tripedalia cystophora (Fig. 17). 



Shape of bell almost exactly that of a cube with rounded edges ; the 

 roof but little arched. The horizontal constriction commonly seen near 

 the top of the bell in the CubomedusaB not present. Proboscis with four 

 oral lobes ; hanging down in the bell cavity generally more than half the 

 depth of the cavity and at times even to the bell margin. In the gelatine 

 of the proboscis an irregular number (15-21) of sensory organs resem- 

 bling otocysts, from the presence of which comes the specific name. 

 Phacelli brush-shaped, composed of from seven to thirteen filaments 

 springing from a single stalk in each quadrant, or rarely from two sepa- 

 rate stalks in one of the quadrants. Distance of the sensory clubs from 

 the bell margin about one-fifth or one-fourth of the height of bell. 

 Breadth of velarium about one-sixth the diameter of bell at margin ; 

 with six velar canals in each quadrant; the canals simple, unforked. 

 Pedalia flattened, shaped like a slender knife blade, about half as long as 

 the height of the bell. Tentacles at greatest extension observed two and 

 a half times the length of pedalia. Sexes separate. Height of bell in 

 largest specimens (reproductive elements mature) eight or nine mm. 

 Breadth same as height or even greater. Color a light yellowish brown, 

 due in large part to eggs or embryos in the stomach pockets. The repro- 

 ductive organs especially prominent by reason of their similar color. 

 Found in Kingston Harbor, Jamaica. 



It will be seen from the above that Tripedalia possesses two of the 



