APPENDIX. 



489 



Bell-cavity about halt" as deep as bell-height. 4 tapering tentacles with swollen basal-bulbs 

 each bearing an ectodermal ocellus on its outer side. The tapering shafts of the tentacles 

 are about 1.5 times as long as the bell-diameter and are armed with numerous, bead-like, 

 swollen rings of nematocysts. Velum well developed. 4 simple, narrow radial-canals. Manu- 

 brium short, simple, conical, with a round mouth-opening without prominent lips. The gonad 

 encircles the ectodermal wall of the stomach and. as growth ''proceeds the thick, ectodermal, 

 germinal epithelium extends outward along the 4 radial-canals,- forming 4 diverticula as in 

 Dissonema, and extending half-way down each radial-canal. Males only were observed. 



The hydroid grows in colonies at a depth of 6 to 15 feet in Lake Ourun where it usually 

 occurs upon Cordylophora. The hydrorhiza is a short, stolon-like tube, the free end of which 

 usually narrows out to form a hydianth-bearing stem. It also gives off in an irregular manner 

 filiform branches about 10 mm. long, each of which terminates in a polypite over 2 mm. long. 

 Only the proximal parts of the branches are covered by the annulated perisarc, the distal 

 ends being quite naked and flexible so that they become entwined around the Cordylophora. 

 The hydranths are claviform with about 4 or 5 hollow, filiform tentacles, although these may 

 range from o to 8. These tentacles arise in a single circlet from the widest part of the polypite 

 and are very contractile. The hypostome is cylindrical, not constricted at its base. Medusa- 

 buds develop from the sides of the body of the hydranth, both above and below the circlet of 

 tentacles. In addition to the production of medusa?, hernia-like outgrowths involving both 

 ectoderm and entoderm appear upon the side walls near the bases of the hydranths and are 

 cast off to form asexual buds. They may dc\ clop tentacles before being cast off. 



This hydroid resembles Hydra and differs from all other hydroids in having hollow 

 tentacles. It bears a certain apparently superficial resemblance to Bougainvillia. The hydroid 

 and medusa have 4 kinds of nematocysts. 



Boulenger studied the variations of 400 specimens of the medusa. One specimen had 3 

 canals, gonads, and tentacles, nine had 5, and one had 6 of these structures. Forty-four of 

 the medusa? had 4 canals and gonads, but their tentacles ranged in number from 5 to 22. Of 

 these, 28 medusa?, had 16 tentacles each, and one had 22. The medusae appear in May in 

 Lake Ourun. 



Slabb:ria brownei. 



Dipurena sp. (>), Browne, 1905, Pearl Oyster Fisheries, Gulf of Manaar, p. 133, plate 2, figs. 1, 2. 



Purcna brownei, Bigelow, H. B., 1909, Mem. Mus. Comp. Zool. at Harvard College, vol. 37, p. 183, plates 7 and 44. 



Bell 5 mm. in diameter, dome-like, rounded, without an apical projection, walls rather 

 thick. 4 tentacles much longer than bell height, with globular basal-bulbs imbedded in the 

 gelatinous substance and surrounded basally by an encircling swelling bearing a prominent 

 ocellus on its outer side. Near the tentacle-bulbs the tentacles are smooth, but outwardly 

 they bear oval, transversely placed, non-ringed clusters of nematocysts. Manubrium 1.5 to 3 

 times as long as the depth of the bell-cavity. Stomach barrel-shaped. Mou'h a round opening. 

 From 1 to 5 ring-like gonads encircling the narrow, tubular part of the manubrium above 

 the somach. . Ocelli yellowish, gonads opaque white. From Ceylon and Manga Reva to 

 Acapulco Harbor, west coast of Mexico. 



Zanclea gemmosa McCrady (see page 88). 

 Zancha gemmosa, Bigelow, H. B., 1909, Mem. Mus. Comp. Zool. at Harvard College, vol. 37, p. 18S, plates 7 and 44. 



Bigelow records the capture of five specimens of this medusa in Acapulco Harbor, Pacific 

 coast of Mexico. 



Heterotiara anonyma Maas ("see page 107). 

 Heteroliara anonyma, Bigelow, H. B., 1909, Mem. Museum Comp. Zool'. at Harvard College, vol. 37, p. 216, plate 41. 



Bigelow records two specimens of this medusa from off the coast of Peru, in the Hum- 

 boldt Current. One had 1 1 and the other 12 tapering tentacles without basal-bulbs. Gonads 

 interradial, entirely separated in the perradii and without cross-furrows. Go'nads opaque 

 yellowish, other parts colorless. Bell 20 mm. in one and 22 mm. high in the other specimen-, 

 both 20- mm. wide. In other respects the specimens resembled the form described by Maas. 



