392 MEDUSA OP THE WORLD. 



Bell 44 mm. wide, flat and thick-walled. A solid apical projection is usually, but not inva- 

 riably present. 8 radially situated clusters of wart-like projections on sides of exumbrella in 

 a zone above bell-margin. These wart-like, or prickle-shaped, projections are bluntly pointed 

 and give the bell an octangular appearance when viewed from the apex or the oral side. They 

 are quite variable in development and increase in size with age. Velum very wide. 130 to 640 

 tentacles of various sizes, the longest and widest being at the bases of the 8 radial-canals, 

 while the interradial, adradial, etc., are of decreasing size and are apparently younger; the 

 tentacles taper gradually and the longest are about as long as the bell-diameter; while the 

 smallest tentacles in mature medusae are about two-thirds as long as the bell-radius. Bigelow, 

 1909, finds that the tentacles consist of a flexible part extending out from the bell-margin, 

 and a stiff" rod-like, outer, terminal portion, resembling a bristle in appearance. The ten- 

 tacles are solid, their entoderm being composed of a row of chordate cells with cubical 

 cells in the flexible and flat tile-like cells in the stiff part of the tentacle. There are 3 to 4 

 elongate lithocyst-clubs per octant, each probably containing 1 to 2 concretions. There are 

 8 wide, ribbon-shaped radial-canals and a wide ring-canal. The stomach is short and 

 conical and the mouth is a wide circular opening. The 8 gonads are elongate and ellip- 

 tical and are developed upon nearly the entire lengths of the 8 radial-canals. 



The entoderm of the stomach and canals ranges from being colorless to bright red. 



The Valdtvia expedition found this species at depths of 300 to 2,000 fathoms in the 

 tropical Atlantic and Indian Oceans off the African coast. It is probably identical with the 

 medusa described by Fewkes from the Gulf Stream off the coast of New England, United 

 States. The Siboga expedition found it among the islands of the Malay Archipelago and 

 Bigelow found it to be common in the eastern tropical Pacific. 



Fewkes states that the gonads are sausage-shaped in his H. minimum, but his specimens 

 were so badly damaged that it will be impossible to determine whether they should be consid- 

 ered identical with H. papillosum, for the radial-canals, stomach, and tentacles were absent. 



Halicreas rotundatum Vanhoffen. 



(?) Halicreas glabrum+H. rotundatum, Vanhoffen, 1902, Wissen. Ergeb. deutsch. Tiefsee Expcd., Valdivia, Bd.3, Lfg. 1, 



pp. 70, 71. 

 Halicreas rotundatum, Vanhoffen, 1902, Wissen. Ergeb. deutsch. Tiefsee Expedition, Dampfer Valdivia, Bd.3, L 'g- >> P- 7'» 



taf. 9, fig. 4.— Maas, 1905, Craspedoten Medusen der Siboga Expedition, Monog. 10, p. 57. 



Bell rounded without an apical projection, 27 mm. wide. No prickle-shaped papillae on 

 exumbrella. 8 wide, short, egg-shaped gonads in middle of the 8 radial-canals. 8 long, radial 

 and about 160 short, interradial tentacles. Mouth a wide, round opening. Color of all ento- 

 dermal parts red, other parts colorless. Tropical parts of Atlantic and Indian Oceans, off the 

 African coast. Lithocysts ( ?) May this not be a variety of H. papillosum ? Maas, 1905, finds 

 that the shape of the bell in H. papillosum, from the Malay Archipelago, is very variable. Is 

 it identical with H. glabrum ? (See text-figure 244.) 



Halicreas glabrum Vanhoffen. 



( ?) Halicreas glabrum+ H. rotundatum, Vanhoffen, 1902, Wissen. Ergeb. deutsch. Tiefsee Expedition, Dampfer Valdivia, Bd. 



3, Lfg. 1, pp. 70, 71. 

 Halicreas glabrum=H. rotundatum ( ?), Maas, 1906, Fauna Arctica, Bd. 4, Lfg. 3, p. 493, Jena. 

 Halicreas glabrum, Vanhoffen, 1902, Wissen. Ergeb. deutsch. Tiefsee Expedition, Dampfer Valdivia, Bd. 3, Lfg. I, p. 70, taf . 



9. fi g- 3- 



Bell 16 mm. high, with a blunt apical projection, and about 16 mm. wide. Higher than 

 H. papillosum. Exumbrella smooth, without wart-like papillae. 8 wide gonads on middle 

 halves of the 8 radial-canals. There are about 30 short, slender tentacles between each succes- 

 sive pair of long, radial tentacles. Thus there are 8 long radial and about 240 short tentacles. 

 Mouth a wide, round opening at extremity of a short, conical neck. Color of entoderm red; 

 other parts colorless. Tropical parts of the Atlantic and Indian Oceans, off the African 

 coast. Lithocysts ( ?) (See text-figure 245.) 



Possibly a variety of H. papillosum ? but more probably identical with H. rotundatum. 



