BOUGAINVILLEA PULVA. 195 



explained as concomitant with a still more advanced stage in growth. I 

 hesitate, however, to unite the two species until more specimens of the 

 L. ocellata form are examined, or until such individuals are found within 

 the range of L. alexandri. 



L. borealis Mayer (: 00") has a much longer manubrium, and the peduncle 

 even more reduced than in either L. alexandri or L. ocellata; but since only 

 three specimens of this species, all males, were examined, it is an open ques- 

 tion whether these differences are constant. The description by Broch 

 (: 05) of L. norvegica is brief and without figures ; but it appears that this 

 species most closely resembles L. borealis in the small number of tentacles, 

 length of manubrium, and simplicity of labial arms. 



Bougainvilleidae Gegenbaur, 1856. 



Vanhoffen ('89); Maas (:05). 



Hippocrenidae McCrady, 1857. 



Anthomedusae with four interradial gonads ; with branched labial ten- 

 tacles ; marginal tentacles in bundles. 



The family divides into three sections according as there are four, eight, 

 or sixteen groups of tentacles. The genera of the last two groups, Rathkea, 

 Lizzia, and Chiarella, are sufficiently well defined, but those of the first, 

 Margelis, Bougainvillea, and Nemopsis, merge into one another to such 

 a degree that it is doubtful whether they should represent more than one 

 genus. The final answer to this question cannot be given, however, until 

 more thorough comparative studies have been made, and especially until the 

 life histories of the various species, their hydroid stages, and the changes 

 which the medusae undergo with growth, have been traced. The family is 

 represented in the "Albatross" collection by a series referable to Bouijain- 

 villea fulva Agassiz and Mayer. 



Bougainvillea fulva Agassiz and Mayer. 



Bougainvillea fulva Agassiz and Mayer, ",)9, p. 102, pi. 2, fig. 6 ; : 02, p. 145, pi. 2, fig. 8; 

 Maas, :05, p. 10, taf. 1, fig. 8, taf. 2, tigs. 9, JO; : 00'', p. ,S7, pi. 2, figs. -1, 5. 



Plate 6, Fig. 7 ; Plate 44, Figs. 5-7. 



Acapulco Harbor; surface; many specimens, from 1 to 7 nun. in diameter. 

 The specimens range from very small up to about the stage represented 



