BlGELOW: MEDUSAE AND SIPHONOPHORAE. 395 



canals and otoporpae, has recently been recorded from the Indian 

 Ocean by Browne (1916) as "Solmaris sp.?" 



In short, the Solmaridae fall naturally into three genera, Solmaris 

 with ring-gonad, and neither canals nor otoporpae, Pegantha and 

 Polycolpa limited as above, though Mayer (1910), uses the genus 

 Pegantha to include all solmarids with localized interradial gonads, 

 irrespective of the presence or absence of peripheral canals or oto- 

 porpae. 



In no genus of Medusae is the delimitation of the various species 

 more difficult than in Pegantha, owing to the unsatisfactory nature 

 of most of the older descriptions and figures; and to the paucity and 

 poor condition of available specimens. And it is so homogeneous 

 that for specific characters we must turn to such minor features as the 

 form of the gonads, the number of otocysts, exumbrella sculpture, and 

 number of tentacles with due regard to its variability. 



On this basis Vanhoffen (1908a, p. 67) reduces the eighteen species 

 listed by Haeckel (1879) to ten, while Mayer (1910) recognizes eleven. 

 But when the various Peganthas are better known, a much more 

 drastic revision will probably be necessary. This it would be idle for 

 me to attempt, without larger series of specimens than are at hand. 

 But it may be of service to outline briefly the present state of our 

 knowledge. 



One species of Pegantha, and one only, P. triloba Haeckel, has been 

 taken often enough, and studied sufficiently (1909a, Vanhoffen, 

 190Sa, 1912a, 1912b) to make its specific features, and their variability, 

 well known. 



It is characterized by well-marked exumbrella sculpture; by long 

 ovate marginal lappets, tripartite gonads, with occasional bipartite 

 and quadripartite variations, 9-16 tentacles, and 18-20 otocysts per 

 lappet. P. biloba Haeckel, with bipartite, and P. sicboldi and P. 

 quadriloba Haeckel with quadripartite gonads, are probably identical 

 with it (Bigelow 1909a); and the Pegantha described by Vanhoffen 

 (1908a) as Polyxenia cyanogramma Quoy and Gaimard, certainly is, as 

 Mayer (1910) has already pointed out. Pegantha pantheon Haeckel 

 (1881) resembles P. triloba in general form and sculpture, and is 

 separable from it only by having eighteen instead of sixteen, or fewer, 

 tentacles, a distinction which may be merely an evidence of extreme 

 variation. Vanhoffen (1908a, p. 67) it is true, credits it with " Funf- 

 Teiligen Gonaden." But Haeckel's figures of the gonad show merely 

 a much wrinkled sac, as might be expected of alcoholic material. 



Pegantha martagon Haeckel has likewise been redescribed recently 



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