430 MEDUSAE OF THE WORLD. 



The radiating stomach-pouches in Haeckel's Cunanthidae extend outward in the radii of 

 the tentacles and terminate without forking at the bases of the tentacles. In the ^Eginidae, on 

 the other hand, the stomach-pouches bifurcate and extend outward even beyond the points 

 of insertion of the tentacles. Accordingly, we may conveniently group these two families 

 under the name iEginidae, distinguishing the subfamilies Cunanthinae with simple, uncleft, 

 radial stomach-pouches, and iEgininae with stomach-pouches cleft by the insertions of the 

 tentacles. Similarly we may combine the Peganthidx and Solmaridae of Haeckel under one 

 family, the Solmaridae. We may thus classify the Narcomedusae as follows : 



ORDER NARCOMEDUS.*. 



I. Family Solmaridae: Without peripheral stomach-pouches. With or without subumbrella sac- 

 cules in the floor of the subumbrella. 

 II. Family ^ginidje : Narcomedusae with marginal stomach-pouches in the radii of the tentacles, 

 (a) Subfamily Cunanthinae, with simple, uncleft stomach-pouches in the tentacular radii. 

 (/>) Subfamily iEgininje, with radial stomach-pouches cleft by the insertions of the tentacles. 



In the following arrangement of genera I have, however, disregarded the subfamilies 

 Cunanthinae and iEgininae and have grouped the genera of both in such a manner as to 

 indicate their probable phylogenetic relationships. It must be borne constantly in mind, 

 however, that our knowledge of the Narcomedusae is still so imperfect that nothing but a 

 provisional classification of the forms can, as yet, be attempted. 



I would regard the genus Solmaris as the simplest anatomically, and possibly also the oldest 

 phylogenetically of the Narcomedusae. The following scheme may possibly illustrate the rela- 

 tionships of the various groups. 



Genus Solmaris. With a plain, circular stomach-margin, without mar- 

 ginal pouches and without saccules in the subumbrella floor of the 

 stomach. 



Family Mamiom. With marginal stomach-pouches, Genus Pegantha. Without marginal stomach-pouches 



but without saccules in the subumbrella floor of the but with saccules in the subumbrella floor of the 



stomach. stomach. 



Vanhoffen, 1907, divides the Narcomedusae into two groups, each group having two 

 families. He distinguishes the groups in accordance with the character of the peripheral 

 canal-system and upon differences in development. He bases his system upon the results of 

 his study of the collection of Narcomedusae obtained by the German Deep-Sea Expedition. I 

 present the scheme of classification he proposes in the Zoologischen Anzeiger, Bd. 32, p. 175, 

 and in Die Narcomedusen der Valdivia Expedition, p. 71. 



1. Diocheteumena. With a well-developed peripheral canal-system. Development indirect through parasitic larvae. 



A. .-Eginid*. With large stomach-pouches and peronial canals (= radial-canals joined by marginal vessels.) 



Genera: Mgina, with 4 to 6 tentacles; Mginura, with 8 tentacles; Mgineta, with more than 10 tentacles. 



B. Peganthidx.' With rudimentary stomach-pouches, long radial-canals and short marginal connecting vessels. 



Genera: Pegantha, when fully-developed, with 10 to 13 tentacles; Polyxenia, when fully-developed, with 16 to 18 ten- 

 tacles; Polycolpa, when fully-developed, with 25 to 30 tentacles. 



2. Adiocheteumena. With rudimentary canal-system and direct development of the medusa from the egg. 



C. jEcinopsidje. With tentacles reduced to half their original number, so that there is a peronial strand without a tentacle 



between every two existing tentacles. 

 Genera: Solmundtlla, with 2 tentacles; jEginofiiis, with 4 tentacles. 



D. Soemarid*. With a tentacle in the radius of each and every peronial strand. 



Genera: Solmundus, with 4 tentacles; Cunoctona, with 7 to 8 tentacles; Solmaris, with 10 to 64 tentacles. 



In my opinion the extreme variability of the marginal canal-system renders it unsuitable 

 for generic distinctions, and in common with Bigelow, 1909, I thus find myself unable to 

 advantageously apply VanhofFen's system to the classification of the Narcomedusae. 



The system proposed by Dr. H. B. Bigelow, 1909, as a result of his important studies 

 of Narcomedusae from the eastern tropical Pacific is essentially similar to that which I here 



