192 MEDUS.E OF THE WORLD. 



of the bell-cavity. The gonads may be pale green or colorless. The entoderm of the ten- 

 tacle-bulbs is black, or pale green, or colorless. The gonads are upon the sides of the 

 stomach and extend even beyond the first bifurcations of the radial-canals. It is found in 

 the Malay Archipelago, and at Acapulco, Pacific coast of Mexico. 



This is identical with the medusa found by Huxley in the Louisiade Islands, North 

 Pacific, and called P. tropica by Browne, 1904. In P. " tropica" however, the medusa- 

 bearing stolons arise from the first branchings of the 4 main canals and not from the 

 second and third points of forking as in Maas' and Bigelow's form. Bigelow's studies have 

 shown, however, that the two are identical, P. tropica being only a young stage. 



P. "tropica" has 16 terminal branches to its 4 main radial-canals. 16 short tentacles, 4 

 stolons at the points of origin of the first branches of the 4 main radial-canals. These 

 stolons are long and end in a knob of nematocysts. On one side the stolon gives rise to a 

 series of medusa-buds, the oldest being nearest the free lower end of the stolon. When about 

 to be set free the budding medusa has 4 simple, unbranched radial-canals and 4 tentacles. 



Proboscidactyla ornata var. gemmifera. 

 Plate 21, figs. 1-3. 



ll'illia ornata, BROOKS, 1880, American Naturalist, vol. 14, p. 670; 1881, Studies Johns Hopkins Univ. Marine Lab., vol. 2, 



p. 144. 



Il'illiit i>finmifera, FEWKES, 1882, Bull. Mus. Comp. Zoo], at Harvard College, vol. 9, p. 300, plate I, fig. 24. 

 Proboscidaci\la pemmifera, MAAS, 1904, Sitzungsber. math.-phys. Klasse kgl. Bayer. Akad. der Wissenschaften, Bd. 35, p. 439. 



BROWNE, 1904, Hydromedusa- Maldive Islands, p. 727. 

 l)\*< unriotti ^emmifera, MAYER, 1900, Bull. Mus. Comp. Zool. at Harvard College, vol. 37, p. 47, plate 8, fig. 17. 



This variety of P. ornata is peculiar in that it gives rise to medusa-buds which are borne 

 upon 4 stolons that arise from the radial corners of the stomach near the points of origin of the 

 4 main radial-canals. Several medusa-buds in various stages of development may usually be 

 seen upon each stolon. When set free, each medusa has 4 simple, unbranched radial-canals, 

 4 well-developed, radially situated tentacles, and 4 small, interradial tentacle-bulbs. There 

 are also 8 centripetal canals alternating with and intermediate in position between the tentacle- 

 bulbs and tentacles. There are no medusa-buds or stolons upon the medusae when set free 

 from the parent. 



All of the budding specimens of Proboscidactyla which have thus far been observed were 

 in the Dyscannota stage, having 12 terminal branches to the radial-canal system and 12 mar- 

 ginal tentacles. Each of the 4 canals which leave the stomach gives rise to 2 side branches, 

 and thus there are 3 terminal canals in each quadrant; 12 in all. It is possible that after the 

 medusa has ceased budding the canals may increase in number so as to become 16. On the 

 other hand, P. ornata var. gemmifera, may never develop sex-cells or possess more than 12 

 canals. The common P. ornata, which lacks medusa-buds and has 16 tentacles and terminal 

 canals, is found wherever the budding variety has been observed, although the budding variety 

 is not known north of Beaufort, North Carolina, while the sexual form is abundant upon the 

 southern coast of New England. For many years it was believed that in this gemmifera form 

 there was constantly but a single cluster of nematocysts over each centripetal canal of the 

 exumbrella, between the tentacles, whereas in the sexual P. ornata there might be i, 2, 

 or occasionally 3, clusters over each canal. In 1903, however, I found two specimens of 

 the gemmifera form which had I, 2, or 3 clusters of nematocysts over each centripetal canal, 

 and therefore resembled the condition seen in the sexual P. ornata. No gonads have been 

 observed upon the manubnum of the gemmifera form and the stomach is therefore smaller 

 and more slender than in the sexual P. ornata. 



P. ornata var. gemmifern is found from Beaufort, North Carolina, southward to the 

 Bahamas. On the whole its close similarity to P. ornata in the Dyscannota stage leads me to 

 believe that it is only an immature or budding variety of Proboscidactyla ornata. 



Proboscidactyla "minima" Browne. 



Proboscidatiyla minima, BROWNE, 1905, Pearl Oyster Fisheries, Gulf of Manaar, Suppl. Report, Roy. Soc. London, 27, p. 136, 

 plate 2, fig. 3. 



Bell hemispherical ( ?),o.75 to I mm. wide, with fairly thin walls. 4 main radial-canals 

 with lateral branches. Number of lateral branches ( ?) 10 to 20 short tentacles 0.25 mm. 

 long with globular basal bulbs. Stomach with 4 longitudinal lobes with the gonads upon their 

 sides. Mouth with a sinuous margin. Clusters of nematocysts on the exumbrella near the 



