306 



MEDUSAE OF THE WORLD. 



In 1897, Hartlaub founded the genus Eutonina to include Eucopidae with 8 adradial 

 lithocysts, numerous tentacles, and neither marginal nor lateral cirri. 4 gonads on the 4 radial- 

 canals. Stomach mounted upon a peduncle. This falls clearly under the amplified genus 

 Eutimium as defined above. 



Eutimium bears the same relation to Eutima as Phortis does to Eirene, as is shown in the 

 following table: 



Haeckel's Octorchidium tetranema (Syst. der Medusen, p. 196, taf. 13, fig. 9) is apparently 

 •a young Eutima which has not yet developed marginal or lateral cirri. 



Eutimium socialis. 



(})Tiaropsis indicate, Romanes, 1876, Journ. Linnean Soc. of London, vol. 12, p. 525; Ibid., 1877, vol. 13, plate 15, fig. I. 

 ( ?) Eutimalphes indicans, Haeckll, 1879, Syst. der Medusen, p. 195. 



Thaumantias , M'Intosh, 1889, Seventh Annual Report Fishery Board of Scotland, p. 282, plate 5, figs. 6-9. 



Eutimalphes indicans, Hartlaub, 1894, Wissen. Meeresuntersuch. Komm. Meere Kiel, Helgoland, Neue Folge, Bd. 1, p. 194. 

 Eutonina socialis, Hartlaub, 1897, Wissen. Meeresuntersuch. Kommiss. Meere Kiel, Helgoland, Neue Folge, Bd. 2, p. 506, taf. 

 22, fign. 1, 3, 4, 6, 7; taf. 20, fign. 19, 20. 



Bell flatter than a hemisphere, 30 mm. wide. Bell-walls thick above, but thin at margin. 

 About 150 short tentacles, no cirri. 8 adradial lithocysts, each with about 12 concretions. No 

 ocelli. Velum small. 4 slender radial-canals and a narrow ring-canal. A large spindle- 

 shaped peduncle extends to level of velar opening. Stomach small, with 4 complexly folded 

 lips. 4 linear, sinusoidally reflected gonads upon the subumbrella parts of the 4 radial-canals, 

 extending not quite to the ring-canal. Stomach, gonads, and tentacle-bulbs are light sepia, 

 other parts colorless. Hartlaub states that the hydroid is a Campanulina. Found at Helgo- 

 land, German Ocean, and off the east coast of Scotland from March to July. 



Romanes, 1885 (International Scientific Series, vol. 49, pp. 104, 105), demonstrated that 

 the ocelli of Eutimium are sensitive to light rays of the visible spectrum, but not to the ultra- 

 violet or to the heat rays. When a beam of light falls suddenly upon a specimen of Eutimium 

 the medusa remains unresponsive for about 1 second and then it contracts violently. In 

 "Tiaropsis* indicans" Romanes showed that the manubrium bends toward any place on the 

 subumbrella which may be stimulated and applies its mouth to the stimulated spot. If, 

 however, we make a short circumferential cut between the stimulated spot and the base of 

 the manubrium, the manubrium merely executes wandering movements, applying its mouth to 

 many places "as if in search of the point from which the stimulus proceeds." Hence the 

 stimulus must proceed radially inward in a straight line from the stimulated spot to the 

 manubrium in order that it may bend toward the stimulated place with accuracy. 



Eutimium scintillans. 

 Eutimalphes scintillans, B.c.elow, H. B., 1909, Mem. Mus. Comp. Zool. at Harvard College, vol. 37, p. 167, plates 5 and 37. 



Bell 10 mm. wide, 5 mm. high. Peduncle short, only 4 mm. long. 29 to 36 tentacles, 

 having neither knobs nor cirri. 8 large lithocysts, each with 2 to 5 concretions. 4 gonads 

 confined to outer third of radial-canals on subumbrella. Gonads pale green. Acapulco 

 Harbor, Pacific coast of Mexico. Common. 



Subfamily EIRENINjE. 



Eucopida: with more than 8 lithocysts. Stomach mounted upon a gelatinous peduncle. 

 Tentacles arise from the bell-margin. 



♦This medusa belongs to the genu*,' Eutimium and is apparently E. socialis. 



