82 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Medusae of Philippines and Torres Straits.* — A. G. Mayer reports 

 on thirty-one Scyphomedusfe from the Philippines, including four 

 new species : Cotylorhiza paclfica, Catostylus toivnsendi, Lycknorhiza 

 bornensis, and Phyllorhiza luzoiii : and on six Scyphomedusre and ten 

 Hydromedusfe from the Torres Straits, the Hydromedusfe including 

 Eutima australis sp. n. Only one Scyphomedusa {Catostylus mosakus) 

 and one Hydromedusa {Eutima australis) are possibly peculiar to 

 Australia ; the others are of wide distribution. 



The discovery of a Philippine species of Cotylorhiza allied to the 

 species known from the Mediterranean is interesting, but the most curious 

 Philippine genus is Lohouema, in which the marginal lobes of the bell 

 are gradually extended and superficially resemble tentacles, tapering 

 gradually throughout their length to pointed tips. They are not capable 

 of contraction, and their function is problematical. 



Mayer gives a general account of the Scyphomedusifi, and we may 

 refer to a few points of special interest. The minute sense-organs, which 

 occur as pigmented specks at regular intervals around the margin, 

 contain calcium oxalate crystals. It is probable that sodium oxalate is 

 constantly forming in the sense-club ; that, the calcium chloride of the 

 sea-water entering the sense-club forms a precipitate of calcium oxalate, 

 setting free sodium chloride, which is a powerful stimulant for the nerves, 

 thus causing the pulsating reaction. Moreover, Gary has shown that if 

 the sense-organs be removed, the first stages in regenerating another 

 wound are slow. If even a single sense-organ be present, regeneration 

 proceeds at once and with rapidity. The pulsation stimulus in jelly- 

 fishes is conducted by the nerves, whereas in the Vertebrate heart it is 

 conducted by the muscles. Nerve conduction in Cassiopea is chemically 

 described as a reaction, in which the cations of sodium, calcium, and 

 potassium take the active part, while magnesium is passive. The sodium, 

 calcium, and potassium appear to be attracted l)y absorption to the 

 surfaces of some negatively-charged celloidal elements of the nerve, and 

 the velocity of nerve conduction is proportional to the degree of con- 

 centration of these absorbed cations. 



The stinging-cells on the tentacles and other parts appear to secrete 

 formic acid. Large jelly-fishes paralyze many fishes ; but some small 

 fishes, accompanying jelly-fishes and even biting off pieces of them, 

 enjoy a protection from larger fishes which dare not venture so near. 

 The gelatinous substance of a jelly-fish may serve as a store of food, and 

 specimens of Cassiopea can live at least forty-two days without food, the 

 weight declining to less than one-hundredth of the original. The loss of 

 weight on each day is, however, proportional to the weight of the animal 

 at the beginning of that day, and thus the lighter the animal becomes the 

 less weight is lost. 



Scyphomedusge are exclusively carnivorous. The largest forms occur 

 in cold seas, where the floating animal life is more abundant than in 

 the tropics. The gastro-vascular system is both " chymiferous " and 

 digestive. The function of the gastric cirri is not known. 



The sexes are usually separate in Scyphomedusge. In rare cases, as 



* Carnegie Inst. Washington, Publication No. 212, pp. 157-202 (3 pis. and 

 7 figs.). 



