LEPTOMEDUS.K — STOMOBRACHIUM, HALOPSIS. 323 



Adult medusa. — Bell about 45 mm. in diameter, about 3 to 4 times as wide as high. The 

 gelatinous substance is not very thick. More than 400 slender tentacles of various sizes; 

 these are not capable of much expansion, and when contracted the extremities are coiled 

 helically. Velum small. 12 straight radial-canals, upon almost the whole length of which the 

 gonads are developed. Stomach is small, not more than one-seventh as wide as bell-diameter. 

 4 large, triangular, crenated lips, trending in the directions of 4 of the radial-canals and placed 

 at right angles to one another. The medusa is colorless. 



This species was occasionally found at Nahant, Massachusetts, in July, but has not been 

 seen since it was studied by A. Agassiz. (See figs. 181 and 182.) 



Stomobrachium (?) stauroglyphum. 



JEquorea slauroglypha, Peron et Lesufur, 1809, Annal. du Mus. Hist. Nat., tome 14, p. 337. 

 Mquorea forbesiana, Gosse, 1853, Naturalist's Rambles Devonshire Coast, pp. 345, 348, plate 24. 



Staurobrachium stauroglyphum, Haeckel, 1879, Syst. der Medusen, p. 225. — Bedot, 1901, Revue Suisse de Zool., tome 9, p. 486; 

 Ibid. , 1905, tome 13, p. 147 (citation of literature to 1850). 



The bell is hemispherical, about 40 to 70 mm. wide. 30 to 100 tentacles. Numerous 

 lithocysts, each with I to 4 concretions, 30 to 70 radial-canals with linear bilamellar gonads on 

 their mid-regions leaving short lengths of both ends free. Stomach as wide as the bell-radius. 

 Very flat and shallow with 4 long, triangular lips with complexly folded margins. Medusa 

 rose-red. English Channel. I am inclined to suspect that this may be merely an abnormal 

 specimen of Mquorea forskalea with a 4-cornered mouth, due to a peculiar state of contrac- 

 tion or to an abnormal condition of growth. 



Genus HALOPSIS A. Agassiz, 1863. 



Halopsis, Agassiz, A., 1863, Proc. Boston Soc. Nat. Hist., vol. 9, p. 219; 1865, North Amer. Acal., p. 99, figs. 143-150. — 



Haeckel, 1879, Syst. der Medusen, p. 21 7. — Fewkes, 1888, Bull. Mus.Comp. Zool. at Harvard College, vol. 13, p. 233. 

 Non Halopsis cruciata, Agassiz, A., 1865, North Amer. Acal., p. 102. 

 Non Halopsis, Maas, 1893, Ergeb. der Plankton Expedition, Bd. 2, K. c, p. 57, taf. 6, figs. 3-6. 



The genus Halopsis was founded by A. Agassiz, 1863, for H. ocellata of the New England 

 coast, north ot Cape Cod. "Halopsis" cruciata A. Agassiz belongs to the genus Mitrocoma, 

 as does also "Halopsis" megalotis of Maas. 



GENERIC CHARACTERS. 



jEquoridae with numerous radial-canals which arise from the periphery of the stomach in 

 4 radially situated groups or clusters. Stomach with 4 lips. There are numerous tentacles 

 and marginal cirri. The lithocysts are of large size and each one contains a large number of 

 concretions. The gonads are situated upon the radial-canals. 



Halopsis ocellata A. Agassiz. 



Halopsis ocellata, Agassiz, A., 1863, Proc. Boston Soc. Nat. Hist., vol. 9, p. 219; 1865, North American Acalepha?, p. 99, figs. 

 143, 150. — Haeckel, 1S79, Syst. der Medusen, p. 217. — Fewkes, 1888, Bull. Mus. Comp.Zool.at Harvard College, vol. 13, 

 No. 7, p. 233, plate 3, fig. 1 (young medusa). — Hargitt, 1904, Bull. U. S. Bureau of Fisheries, vol. 24, p. 51. 



Adult medusa. — Bell about 70 mm. in diameter and about 4 times as broad as high. The 

 gelatinous substance of the bell is not very thick. A large number of long tentacles, with 

 hollow, conical, basal bulbs and about an equal number of short, slender, contractile cirri upon 

 the bell-margin. 40 to 80 large lithocysts, 3 to 6 between each successive pair of radial-canals; 

 each lithocyst contains 12 to 14 concretions arranged in two rows. Velum small. The radial- 

 canals arise from the margin of the stomach in 4 radially situated clusters. There are usually 

 16 radial-canals, there being 3 to 5 canals in each ekister. These canals are straight, and 

 the linear gonads are developed upon about three-quarters of their length. The stomach 

 is cruciform and only about one-quarter as wide at the bell-diameter. The manubrium 

 is short and there are 4 prominent radially situated lips. The medusa is colorless, with 

 the exception of the gonads, which exhibit a slight grayish or pinkish tinge at the time of 

 spawning. 



