308 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.37. 



Staurofliora laciniata is a common boreal species. On the Ameri- 

 can coast it occurs only occasionally south of Cape Cod. Hartlaub 

 ('97) has recorded what is probably the young of this species from 

 Heligoland, and it is probable that the S. arctica of Haeckel ('79) 

 from Spitzbergen is identical with S. laciniata. 



MELICERTUM CAMPANULA ( Fabricius). 



Plate 31, fig. 1; plate 32, fig. 1. 



Medusa campanula Fabricius, 1780, No. 360. 



Melicertum caynpanula A. Agassiz, '62a, p. 96; '65, p. 130, figs. 202-214. 



Haeckel ('79) has pointed out that the identity of Fabricius' spec- 

 imens with those subsequently described by A. Agassiz ('65) under 

 the name Melicertum campanula is doubtful, owing to the unsatis- 

 factory nature of Fabricius' account. But since it is improbable 

 that any better identification of Fabricius' material can ever be made, 

 it will add to the stability of nomenclature to accept the identifica- 

 tion of A. Agassiz, who has fully described and figured the species. 



This common northern form is represented in the collection as 

 follows : 



Fogo Island, Newfoundland, July 19, nine specimens in early 

 growth. 



St. Pierre, off Newfoundland, three specimens, all about 15 mm. 

 high by 12 mm. in diameter, with mature sexual products. 



Although this species has been thoroughly figured and described 

 by A. Agassiz ('65), the structure of the tentacular organs deserves 

 fresh stud}^, since Maas (:05) has raised the question whether or not 

 there are cirri and knobs as well as developed tentacles. Haeckel 

 ('79) has made the presence or absence of such secondary marginal 

 organs the basis for generic distinction, Melicertidium having, Meli- 

 certum lacldng them. Maas ('97, :05), however, has abandoned this 

 criterion, and suggests, from A. Agassiz' figures, that on fresh exam- 

 ination, cirri and knobs will be found in M. campanula. The evidence 

 in the present series indicates, however, that there is only one class 

 of marginal organ in this species, i. e., tentacles, though these develop 

 continuously and it is probable that not all ever reach the final con- 

 dition. 



In the earhest stage in the present series (specimen 1.75 mm. high 

 by 2 mm. in diameter), there are eight large radial tentacles, eight 

 well-developed, though smaller, interradial tentacles, and in each 

 octant two adradial elements which show all stages from mere knobs 

 to very small tentacles with basal bulbs and terminal filaments. 

 Several of the smallest elements, moreover, closely resemble the cirrus- 

 like structures figured by A. Agassiz. 



