MEDUSA. I. .J 



has demonstrated that the development of the eggs takes place in the genital folds, and that the 

 larvEe leave these folds in the shape of actinulae. 



It is beyond all doubt that the species Staurophora vitrea Sars, ^Staurophora Kcitkti Peach, and 

 Statirostoma arctica Haeckel are identical with Staurophoya laciuiata Agassiz. Since Bigelow (1913, 

 p. 27) has seen a number of specimens from the same regions, where Mertens found the medusa; 

 described by Brandt as Staurophora iiicrloisii, and has had the opportunity of comparing these 

 specimens from the Pacific with specimens from the Atlantic, it may be stated definitely that the species 

 of Brandt and Agassiz are identical. The Staurophora discoidea described by Kishinouye (1910) is 

 only separated from mertensii "by the more numerous lateral folds of the genital gland", the number 

 of which was 17 in merfensii. The description shows that this Japanese medusa in no respect differs 

 from the Atlantic form of Staurophora. Thus all Staurophora from the northern seas belong to one 

 and the same species, Staurophora merfensti Brandt. — In a paper, published in Danish (1914, p. 420), 

 I have stated that Staurophora falklandica Browne also belongs to the same species. This fact will 

 be further demonstrated below. 



Van h of fen mentions this species from the Atlantic outside the Bay of Biscay and from the 

 Indian Ocean (1911, p. 219), further from the southern Atlantic between Trinidad and St. Helena and 

 north-east of St. Paul (191 2, p. 366). In the last-named paper he also describes a new species, Stauro- 

 phora aiitarcfica from the antarctic Sea. I feel convinced that none of these medusae belong to the 

 genus Staurophora. The specimens were all quite small, and \^anh6ffen found that they agreed 

 with Hartlaub's description of the young Staurophora from Heligoland. Common for the latter and 

 Vanhoffen's small medusa; is a general likeness to a young Tiarid. The medusa; from the Indian 

 Ocean (and the Bay of Biscay) are r — 18 mm wide with 4 — 64 tentacles. The 3 weeks old specimens 

 described by Hartlaub were 10 mm high and a little broader, though far from 18 nun, and they had 

 already more than 100 tentacles and, besides, a number of cordyli; the latter are not found in \'an- 

 hoffen's medusa;. In Hartlaub's specimens no traces of gonads were yet visible; Vanhoffen, 

 on the other hand, mentions visible traces of gonads as groo\es in the walls of the stomach in some 

 of the specimens from the Indian Ocean (he does not state how man}- specimens or what sizes) as 

 well as in the specimen from the southern Atlantic, which was only 5 mm high. Vanhoffen rightly 

 calls attention to the fact, that the gonads being developed as grooves in the walls of the stomach is 

 a feature pointing towards the Tiaridcr. Btit in Staurophora the gonads are not placed in grooves, but 

 in lateral extensions developed along the line by which the cross is attached to the subumbrella. 

 F'inally, Vanhoffen states that the specimens from the Indian Ocean (and the Bay of Biscay) are 

 provided with ocelli on the outer (abaxial) side of the tentacular bulbs. This statement might 

 possibly be due to a slip of the pen or a misprint; but in the figure of the medusa from the southern 

 Atlantic (1912, Taf. XXV, fig. 3) the ocelli are clearly drawn as being abaxial. Altogether, I feel sure 

 that the medusa;, referred by Vanhoffen (in 191 1 as well as in 1912) to Staurophora laciuiata, are 

 really some kind of young Tiaridce. The same is undoubtedly the fact with regard to ''Staurophora 

 antarcticd\ This medusa is 10 mm in diameter and has 8 tentacles; the stomach is deep brown with 

 groove-shaped gonads. 



Tlie Ingolt'-Expedition. V. 8. ■ *' 



