stalked medusas are only too easy to overlook, for 

 most are only 1 inch or so across the open flaring 

 end of the umbrella, and are the same brownish or 

 greenish color as the seaweeds to which they cling. 

 A few come in prettier shades of blue, violet, pink, 

 or orange. The pendant mouth stalk is four-cornered, 

 with little lobes, and ingests small animals that come 

 its way. If the food supply runs low, some stalked 

 jellyfishes can glide to new stations, adhering to solid 

 support by the tentacles and by adhesive pads that 

 alternate with the clusters of tentacles around the 

 margin of the umbrella. They are said to breed at all 

 seasons, and the egg develops into a stalked, trum- 

 pet-shaped adult without going through the splitting 

 stage typical of many scyphozoans. Best known of 

 the stalked jellyfishes are Haliclystiis and Liiceniaria. 



THE CUBOID A L JELLYFISHES OR 

 SEA WASPS 



In tropical or subtropical bays or harbors, or some- 

 times in the open sea, sea wasps had best be recog- 

 nized by their cuboidal shape, not by testing their 

 highly venomous sting. The colorless body has four 

 flattened sides, and from each corner springs a ten- 

 tacle or a group of tentacles, these often with some 

 color. Feeding mostly on fish, they back up their vo- 

 racious appetites by the strongest swimming habits 

 known among jellyfishes. The cuboidal umbrella 

 may contract up to 150 times a minute. Though many 

 are only 1 or 2 inches high, some measure as much as 

 10 inches from margin to top of umbrefla. The best- 

 known genus of sea wasps, Curybdea. is luminescent. 

 In spite of the evil reputation of Caryhdea alata in 

 the tropical Pacific, Atlantic, and Indian oceans, it is 

 members of this genus that are relished in the Gilbert 

 Islands (p. 77). The most fearsome genus of ail is 

 Chiropscdmus, especially in Philippine waters. Phil- 

 ippine and Japanese fishermen call this the "fire me- 

 dusa" and keep their distance. Chiropsalmus qiiadri- 

 gatus, notorious for its rapidly fatal sting, is known 

 from northern Australia, the Philippines, and the In- 

 dian Ocean. A related but less dangerous form oc- 

 curs in the Atlantic from North Carolina to Brazil, 

 and also in the Indian Ocean and northern Australia. 



THE CORONATE JELLYFISHES 



The coronate or crowned jellyfishes are recognized 

 by a prominent horizontal groove that encircles the 

 umbrella. Below this crowning groove the umbrella 

 margin is furrowed by vertical grooves, each ending 

 in the middle of one of the lobes of the often deeply 

 scalloped edge. The beautiful sculpturing of these 

 masses of jelly reminds one of some of the gelatin 

 desserts that have been shaped in grooved, domelike 

 metal molds. Coronate jellyfishes may measure 6 

 inches across, but most are under 2 inches. Though 

 this is chiefly a deep-water group, some species, like 



the flattened Nausitho'e, are common in all warm, 

 shallow waters. Nausitho'e is often seen in the Baha- 

 mas and in Florida, and is carried northward along 

 the American Atlantic coast. It occurs also in more 

 northern Atlantic waters. Periphylla hyacinthina, 

 with a high, narrowly pointed umbrella and a beau- 

 tiful purple color, is common in deep waters all over 

 the world and is often seen at the surface. 



THE DISK JELLIES 



Not all the members of this group are as disklike 

 as the common name suggests, but compared with 

 other scyphozoans they do have flattened umbrellas 

 when relaxed. They look hemispherical when con- 

 tracted in swimming. Large and bulky kinds, espe- 

 cially Cyanea, are often called sea blubbers. The 

 technical name, Semaeostomeae, makes a poor han- 

 dle for these most typical of scyphozoan jellyfishes, 

 which are the ones most likely to be seen in temper- 

 ate waters. All are of moderate to large size, ranging 

 from 2 inches to 2 feet across. The giant Cyanea, re- 

 ferred to on page 00, is exceptional. Disk jellies oc- 

 cur in all coastal waters, especially warm and tem- 

 perate ones, often in great shoals of many thousands 

 of individuals, usually at seasonal intervals. The um- 

 brella margin is often scalloped into eight lappets, 

 sometimes more. The four corners of the mouth are 

 drawn out into four long, frilled lobes, each folded 

 down the middle and forming a trough to direct food 

 into the mouth. 



Unfettered by a fixed stage, the lovely Pelagia is 

 the only disk jelly free to roam the open seas. The 

 purple-rose umbrella, shading into blue, is 2 inches 

 or more across, and the scalloped margin has sixteen 

 notches, eight tentacles, and eight sense organs; the 

 tentacles and sense organs alternate in the notches. 

 When Pelagias glide past a ship at night they glow 

 like white balls of fire. Seen at a distance, they show 

 as large winking spots instead of as the even glow 

 caused by billions of luminescent protozoans. Pelagia 

 noctiluca is abundant in the Mediterranean, and it is 

 probably the same species that is swept up the Amer- 

 ican coast by the Gulf Stream and that delights Scot- 

 tish observers whenever it arrives in the North At- 

 lantic Current. 



Also luminescent is the graceful compass jellyfish, 

 Chrysaora hysocella, strongly marked on the um- 

 brella with radiating V-shaped streaks. Toward the 

 end of summer it appears in great numbers in Euro- 

 pean Atlantic waters. 



Most widely distributed of the true jellyfishes is 

 the moon jelly, Amelia aiirita. In all oceans, and 

 from polar waters to the equator, it seems to vary 

 little, though probably there are several subspecies 

 that breed at different times and require different sea 

 temperatures. When relaxed and drifting it is a shal- 



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