MEDUSAE OF WOODS HOLE REGION. 



55 



Family AGLAl'RID.S. 



KEY Ti> THE GENERA. 



A. Gonads 8. 



1. Gonads borne on radial canals iglantha 



2. Gonads borne on manubrium Iglaura 



B. Gonads I. or sometimes 2, 



:!. Gonads 2, on opposite sides of umbrella Pi rsa 



AGLAURA Peron & Lesueur ( L809 



Aglaura hemistoma Peron & Lesueur. Text cut. 



Aglaura hemistoma Peron & Lesueur. Tableau des Meduses, 1809, p. 351. 

 Aglaura peronii Leuckart, Archiv fur Naturgeschichte, Jahrgaug 22, 1856, p. 10. 

 Aglaura hemUtomn ear. /mm/>/V<i<i Minis, Die t'raspedoten Medusen der Plankton-Expedition, 1893 

 p. 26. Hargitt. Biological Bulletin, Vol. IV, 1902, p. 14. 



Medusa in form of a cylinder, somewhat octagonal as viewed from either 

 pole. Average size 4 mm. in height by about Half as broad. Radial canals 

 8, extending downward upon the long gelatinous manubrium, which hangs 

 freely in the subumbrellar cavity for about two-thirds its extent. Gastric 

 portion rather short ami with prominent four-lobed oral lips. Gonads, 4 or 5 

 in number, are suspended as finger-like processes from the lower portion of 

 the gelatinous peduncle. Velum well developed and normally having the aspect jr/laura hemisUma. 



shown in the figure, though often infolded in similar form within the bell. Tin- 

 tentacles were in nearly every case entirely lacking or so badly distorted as to make impossible any 

 accurate determination of either their number or character; usually, however, the basal portions 

 showed with sufficient clearness to enable a recognition of their presence, and by comparing a number 

 of specimens an approximation as to the number was possible, as shown in the figure. Ontogeny 

 entirely unknown. 



Colors. — Bell very transparent; oral portion of the manubrium pale reddish; gonads pale 

 brownish to yellow, or whitish. 



Distribution. — Region of the Gulf Stream, some till miles south of Marthas Vineyard. 



AGLANTHA Haeckel (1879). 



Aglantha digitalis (O. F. Muller). Text cut. 



Fab- 



Medusa digital* 0. F. Muller. Prodromus Zoologiea Daniea, 1766, p. 233. 

 ricius, Fauna Groenlandica, 17*0, p. 366. 



Melicerta >ti;iita/r Penni t v Lesueur, Tableau des Meduses, 1809, p. 352. 



Eirene >liiiit>il< Esehscholtz, System der Acalephen, 1829, p. 95. 



Circe rose i Forbes. British Naked-eyed Medusas, 1818, p. 34. L. Agassi/, Contribu- 

 tions Natural Hist..ry United States, Vol. IV. 1862, p. 349. 



Trachynema digitate A. Agassiz, Noit'i American Acalephae, 1865, p. 57. 



Aglantha digitalis Haeckel, System der Medusen, 1879, p. 272, 



Medusa elongate bell-shaped, with rather sharp apical projec- 

 tion. Radial canals S, rather wide and extending downward upon 

 the long gelatinous peduncle. Marginal tentacles numerous, but 

 fragile and in many cases detached, apparently by the medusa when 

 brought into captivity. Otocysts 4, with reddish colored otoliths. 

 Gonads 8, suspended like sausages from the upper portion of the 

 radial canals. Velum strong and usually folded within the bell 

 cavity. Gastric portion of the manubrium comparatively small, 

 mouth with four everted lips. The medusa presents different 

 aspects at varying ages, as pointed out by A. Agassiz, the young 

 Adult specimens 1'5 to 35 mm. high. Ontogeny entirely unknown. 



Colors.— Bell transparent, slightly pinkish, gonads milky white. 



Distribution. — Taken at various points within the region, chiefly Woods Hole, March to May. 



Aglantha digitalis. After A. Agassiz. 

 being shorter and more spherical 



Reported by Agassiz from Massachusetts Bay; by Fabricius from Baftins Bay. 



