248 THE VOYAGE OF H.M.S. CHALLENGER. 



Forskaliopsis seem to be looser, and their organs more irregularly scattered than in the 

 preceding Forskalia. The palpons of the former are much more numerous, often three, 

 four, or more arising from a common pedicle. Perhaps other constant differences may- 

 be found between these two genera, which are also rather different in external appear- 

 ance. Forskaliopsis is one of the largest and most splendid Physonectse ; its size 

 in the fully expanded state attains more than a metre, and the number of nectophores as 

 well as of siphons amounts in the larger specimens to five hundred or more, the number 

 of bracts to several thousands. I observed a gigantic representative of this splendid 

 genus, Forskaliopsis magnified, distinguished by the blackish-brown colour of the 

 siphons and cnidocysts, in 1881, in the Indian Ocean ; but unfortunately it was destroyed 

 before I could examine it sufficiently. 



Genus 53. Bathyphysa, 1 Studer, 1878. 



Bathyphysa, Studer, Zeitschr. f. wiss. Zool., Bd. xxxi. pp. 21, 24. 



Definition. — Forskalidse with loose cormidia and unsegmented trunk of the sipho- 

 some. Gonodendra distylic (?), arising from the trunk, separate from the siphonal 

 pedicles. Siphons with hepatic villi and a pair of lateral wings. Nectosome probably 

 with palpons between the nectophores (?). 



The genus Bathyphysa (perhaps the representative of a separate family. Bathy- 



physidse) was established in 1878 by Studer for a gigantic deep-sea Siphonophore, 



which surpasses all other animals of this class in the extraordinary size of the siphons 



and of the gonodendra. It was taken by the S.S. " Faraday" in 1875, on the occasion 



of the third Atlantic Cable Expedition, and brought up by a grapnel from depths of 



1000 and 1780 fathoms, in the North Atlantic (lat. 43° 45' N., long. 43° 36' W.). The 



fragments of this most interesting genus, preserved in the Zoological Museum of Berlin, 



are unfortunately very incomplete, partly without connection, and do not allow us to 



compose a satisfactory idea of the complete structure and the natural affinities of the 



genus. The strong tubular trunk of Bathyphysa abyssorum, which even in the highly 



contracted state has a length of more than a metre, is divided into two halves of very 



unequal thickness. The proximal or superior half is only 3 to 5 mm. in diameter and is 



the trunk of the nectosome ; it bears at its apex an ovate pneumatophore of 20 mm. in 



length, and beyond it numerous lateral apophyses (not mentioned by Studer, but figured 



by him in fig. 28, loc. cit.), which are probably the bases of the pedicles of the detached 



and lost nectophores. The distal or inferior half of the trunk is much thicker (10 to 



15 mm. in diameter), laterally compressed, and beset in the ventral median line with two 



series of numerous appendages, siphons and gonodendra alternating. The thin tubular 



pedicles of the siphons attain a length of 20 centimetres, and bear numerous pisi- 



1 Bathyphysa = Deep-sea-float, (ia.8vs, <?£w«. 



