SCYPHOMEDUSAE 351 



different and mostly insufficient way ; and because the various descriptions do not agree 

 with each other. 



Among the series oi Periphylla in the present material I found twenty-nine specimens, 

 all of which I at first identified as large dodecabostrycha, but later on I found that there are 

 intermediate forms between them and the large blunt specimens described hitherto as 

 regina. Thus it became impossible for me to keep both forms separate and I identified 

 the specimens as regina. I must confess, however, that I did not find a single specimen 

 uniting all the four characters enumerated by Broch (1913, p. 8) for regina. It is there- 

 fore possible that another medusologist may consider that the present series of twenty- 

 nine specimens consists exclusively of large dodecabostrycha without a single regina. 

 This is the more likely as the specimens differ in some morphological respects from the 

 descriptions hitherto given by the various authors. 



The reasons for the instability of the species regina lie in the facts that only relatively 

 few well-preserved specimens of this so-called species have been captured and studied, 

 that there is no good figure of it in the literature, and that Haeckel's description of 

 Periphema regina is in many respects insufficient because the type specimen was badly 

 damaged. Furthermore, the various authors differ in their appreciation of the cha- 

 racters for systematic purposes. One takes the shape of the bell or of the stomach and 

 lack or presence of a "Stielcanal", another the more or less globular shape of the 

 pedaHa. 



Let us examine the literature on this point : 



The Challenger Expedition (Haeckel, 1881) captured a specimen in broken frag- 

 ments in the sub-Antarctic, south-west of Kerguelen, 62° 26' S, 95° 44' E, St. 156, from 

 a depth of 1975 fathoms. Haeckel gives a poor description of this type specimen under 

 the name Periphema regina. No figure of the external shape of the medusa could be 

 given, but only of a fragment of the border of the umbrella, with pedalia, lappets and 

 tentacles (pi. xxiv, fig. 2). The bell is said to be nearly as high as broad; the pedalia 

 are not figured as globular or semiglobular, but are described (p. 85) as being slightly 

 vaulted and comparatively small, the rhopalar being figured longer and narrower than 

 the tentacular ones. Mayer (19 10, p. 547) believes them, according to Haeckel's figure, 

 to be rectangular and longer than wide. Browne (1910), who saw the type specimen of 

 regina in the British Museum, found it to consist "only of a few fragments of little 

 scientific value" (p. 43). 



The Valdivia Expedition (Vanhoeffen, 1903) brought home two specimens only of 

 P. regina from the Antarctic (St. 120, 42° 17' S, 14° i' E, in the West Wind Drift, 

 closing net, iooo-i50om. depth and St. 136, 55° 57' S, 16° 14' E, in the Antarctic 

 Drift, vertical net, 2000 m.). The other stations, 264 and 271, where P. regina has been 

 collected, are in the Indian North Equatorial current and in the Gulf of Aden, from 

 1079 and 1200 m. depth. The very beautiful figure given by Vanhoeffen (1903, pi. ii, 

 fig. 6) is not accurate. It shows very well the external shape, with low dome, rounded floor 

 of the stomach and lack of " Stielcanal ", but there is no trace of a coronal furrow and the 



