ii2 DISCOVERY REPORTS 



tooth (Text-fig. 54A). The hydroecium is less deep than that in both L. fowleri and L. hardy. The 

 somatocyst, which alters shape, presumably in accordance with the amount of fat in store, may be 

 spheroidal or egg-shaped, often much flattened, but its base remains close to the basal facet of the 

 nectophore, and it usually reaches to the ventral facet. The canal leading immediately to the somato- 

 cyst is well on the baso-dorsal side. In dorsal view it will be noticed that the mouth-plate on the left 

 (morphologically the right-hand one) is much broader than the other (Text-fig. 54 B). Both halves of 

 the mouth-plate are much less deep than in L. hardy and L. fowleri. It may be found advisable later 

 on to include the three species fozvleri, hardy and challengeri in a separate genus. The eudoxids of all 

 are known but have not all been described and figured. 



The holotype specimen (Text-fig. 54A, B) bears the B.M. (Nat. Hist.) Register number: 1953.8.11.1. 



Cpa cped 



Text-fig. 54. Lensia challengeri, sp.n., anterior nectophore from 'Challenger' St. 104, Oct. 1950; A, lateral view, x 12; 

 B, dorsal view of mouth-plate, x 35. Lensia hotspur, anterior nectophore, Gulf of Aqaba, Manihine St. 1 ; C, antero-lateral 

 view of base, X40; C 1 , dorsal view of mouth-plate; D, lateral view, x 12; E, lateral view of base, x 25. 



Lensia cossack Totton, 1941. 



This species was reported by Browne from Chago, Mauritius, Farquhar and Amirante under the 

 name of Diphyes subtiloides. I have re-examined eight of the eleven anterior and the two posterior 

 nectophores which are now in the British Museum Collection. 



Lensia subtiloides (Lens & van Riemsdijk), 1908. 



The record by Browne from Chagos, Mauritius, Farquhar and Amirante is not for this species but 

 for Lensia cossack. I have re-examined the specimens in the British Museum Collection. 



L. subtiloides and one of its associates, Diphyes chamissonis are not widely spread over the oceans. 

 They were the only two really abundant Siphonophores that the Great Barrier Reef Expedition of 

 1928-9 found in the Barrier Reef lagoon, where Lensia subtiloides became relatively very rare when the 



