PART II. 



HYDROMEDUSJE OF TORRES STRAITS, AUSTRALIA. 



DESCRIPTION OF SPECIES. 



Genus STOMOTOCA L. Agassiz, 1862. 



Stomotoca, AGASSIZ, L., 1862, Cent, Nat, Hist, U. S., vol. 4, p. 347. MAYER, 1910, Medusae of 

 the World, vol. 1, p. 108 



GENERIC CHARACTERS. 



Stomotocini with 2 long diametrically opposed perradial tentacles with 

 hollow basal-bulbs. With or without other smaller tentacles or cirri, and 

 with or without abaxial, cctodermal ocelli at the bases of the tentacles or cirri. 

 The interradial or adradial gonads are complexly folded and may migrate 

 outwards more or less along the 4 radial-canals. These radial-canals are 

 broad and flat and there is a well-developed circular canal. The hydroid 

 appears to be Perigonimus. 



Stomotoca turrida (Mayer). 

 (Plate 1, Fig. 1.) 



Dissonema turrida, MATER, 1900, Mem. Mus. Comparative Zool. at Harvard Coll., vol. 37, p. 44, 

 plate 2; also, 1910, Medusa; of the World, pp. 116, 490, plate 10, fig. 1; plate 22, fig. 1. 



Amphintma turrida, BIGELOW, H. B., 1909, Mem. Mus. Comparative Zool. at Harvard College, 

 vol. 37, p. 200, plates 7, 40, 43, and 44. 



This medusa was fairly common at the Murray Islands, Torres Straits, 

 Queensland, Australia, late in September 1913. H. B. Bigelow found it in 

 Acapulco Harbor, Pacific coast of Mexico, and it is common at Tortugas, 

 Florida. The largest of the Murray Island specimens was still immature, the 

 bell being only 4 mm. in height, whereas at Tortugas, Florida, the bells of 

 mature medusae are usually about 6 mm. high. It differs from the Tortugas 

 medusae in its duller color, the green being absent, and there are no ocelli on the 

 abaxial sides of the 2 main tentacles. The marginal cirri are only beginning 

 to develop and the adradial gonads are beginning to migrate outward along 

 the radial-canals. The absence of ocelli at the bases of the 2 long ten- 

 tacles may be due to the immaturity of the specimen, for they are sometimes 

 absent from the tentacle bases of small medusae at Tortugas, Florida, Alto- 

 gether the differences between the tropical Pacific and the tropical Atlantic 

 medusae appear to be too slight to warrant their specific separation. This 

 species is closely related to Stomotoca octadra, but differs in having numerous 

 marginal cirri each with an abaxial, cctodermal, basal ocellus. 



Genus CYT^EIS Eschscholtz, 1829. 



Cytceis, ESCHSCHOLTZ, 1829, System dor Acalephen, p. 104. 



GENERIC CHARACTERS. 



Cytaeidae with 4 simple, radially placed, marginal tentacles, and with 4 or 

 more simple, unbranched, oral tentacles. 



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