SEMAEOSTOME^ CYANEA. 



597 



(^? ?} Melusina formosti, Haeckel, i88i, Report Deep-Sea Medusa; Challenger Exped., Zool., vol. 4, p. i. 



Cyanea postehii, Brandt. 1838, Mem. Acad. Sci. St. Petersbourj^, .Sci. Nat., ser. 6, tome 4, p. ^^75, taf. 12, 13, i^a. — Haeckel, 



1880, Syst. der Medusen, p. 1^32. — Vanhoffen, 1906, Nordisches Plankton, Nr. 11, p. 55, fig. 21. — Maas, 1906, Fauna 



Arctica, Bd. 4. Lfg. 3, p. 506. 

 Cyanea imporcata^ Norman, 1865, Nat. Hist. Trans., Northumberland and Durham, vol. 1, p. 11, i taf. (a young Cyanea from 



the British coast). 

 Cyanea citreu, Kishinouve, 1910, Journal College of Sci. University Tokyo, vol. 27, art. 9, p. 16, plate 4, figs. 16, 17 (this is C. 



jerrugineti). 



It is practically impossible to draw any fixed distinctions between the various forms of 

 the great Cyanea of the North Atlantic. Intergrading forms are commonly met with and 

 many of the races are separated only geographically or upon color distinctions which are 

 neither wholly characteristic nor stable. Medusa capiUata Linne, 1746, is the oldest name 

 applied to any ot these medusae. The following are probably all varieties of one and the same 

 species, C. capillata: 



Cyanea capiUata. Bell about 500 to 1,200 mm. wide. Ocular and intcrocular clefts of bell-margin not sharp and narrow, 

 but with evenly rounded curves. Bell, palps, and tentacles reddish or yellowish-brown, with rose-colored or red gonads. 

 Vanhoffen, 1906, states that when the bell is 13 mm. wide there are 7 tentacles in each adradial cluster, the middle 

 one of eacli group being the longest. When 20 mm. wide there are 15 tentacles in each cluster with 3 long ones 

 in the middle. When 4! mm. wide there are 35; and when 86 mm. there are 63 tentacles. This variety is not un- 

 common in the English channel. North Sea, and coast of Norway in summer and autumn. 



Var. lamarckii. Distinguished by the decided blue color of the bell and palps, the color being lighter at the margin 

 than at the center of the bell. Gonads and tentacles nearly white. In other respects this form resembles C. capillata, 

 Vanhoffen states that when the medusa is 43 mm. wide there are only 20, and when 85 mm. wide only 31 tentacles 

 in each group, thus being only about half as many as in the typical C. capillata of the same diameter. On the other 

 hand the gonads in a medusa of C. lamarcki 43 mm. wide are about as long as the palps, thus being larger than in 

 C. capillata. This form is found in the English channel along the coasts of France and Great Britain, at Helgoland, 

 and in the entrances to the Baltic, but it does not extend into the Baltic. It becomes 300 mm. wide. 



Var. arctica. Supposed to be distinguished from the first two forms by the indistinctness of its rliopalar lappets which 

 do not project as far beyond the general contour of the bell-margin as in C. capillata. It is very large, though speci- 

 mens over Soo mm. in diameter are rarely met with. The bell is very variable in color but is usually rich brown and 

 yellow, with deeply colored gonads and rich rosin-yellow muscles and tentacles. It is found off the American coast 

 north of Cape Cod, where it is abundant during the summer, becoming mature and disappearing in early autumn. 



Fig. 381. — Cyanea ferrugtneaj according to Eschscholtz, after Vanhtiffen, in Nordisches Plankton. 



Var. fulva, A small yellowish-colored variety of C. arctica which ranges from Cape Cod southward to the Carolina 

 coast. It is rarely over 200 mm. wide. At Newport, Rhode Island, it becomes mature early in June and is not seen 

 in July, but on the coast of New Jersey it is found in August. 



Var. nozakii. Similar to C. julva, but milk-white in color. Found in the Inland Sea of Japan. 



Var. versicolor. A pink-colored southern variety of Cyanea julva^ which is even smaller, rarely more than no mm. 

 wide. It forms large swarms during the winter and spring off the coast of the United States between Cape Hatteras, 

 North Carolina, and southern Florida. 



Var. ferruginea. Of the North Pacific coasts of America and Asia. It is a variety of C. capillata and is apparently identical 

 with the variety C *' arctica.'* It becomes about 450 mm. wide and is light-yellow or orange with the stomach and radial 

 pouches light-brown. The gonads are yellow and the tentacles reddish, although these colors are probably somewhat 

 variable as in other forms of Cyanea. 



Var. posteliii appears to be only a local variety of C. capillata. It is found in the North Pacific from the Aleutian 

 Islands to Oregon and is distinguished by the 16 well-developed clefts which flank the rhopalar lappets and are about 

 half as deep as the adradial clefts; moreover, according to Mertens, the contours of the lappets are evenly rounded 

 and even the clefts are not narrow, but widen inwardly with rounded contour. A modern study of this medusa is 

 to be desired, for it is possible that Mertens over-emphasizes these peculiarities. The medusa is found between 

 Sitka and the Aleutian Islands, Alaska. 



The following is a detailed description oi' Cvatiea ''arctica'^ of the coast of North America: 



Adult medusa. — The disk is quite flat and lenticular and attains a diameter of 2,300 mm. 



Medusae of this size are very rare, however, and the majority are not over 800 mm. wide. The 



