REPORT ON THE SIPHONOPHORiE. 299 



Genus 62b. Stephonalia, 1 n. gen. 



Definition. — Stephalidae with a double or multiple corona of nectophores, arranged in 

 two or several circles. Tentacles of two different forms and unequal sizes, larger 

 proximal and smaller distal. 



The genus Stephonalia, represented by the remarkable deep-sea species figured in 

 PI. VI., is closely allied to the preceding genus, Stephalia (PI. VII.), and was formerly con- 

 founded by me with it. But a closer examination and comparison of the two forms showed 

 some peculiar differences between them, which now seem to me to possess a generic value. 

 Firstly, the corona of nectophores, although very incompletely preserved, seems to be 

 composed of two (or even three) circles ; and if this be true then Stephonalia agrees 

 in this point with Rhodalia, and bears to it the same relation as Stephalia does to Auralia 

 (both with a single circle of nectophores). A second difference between Stephalia, and 

 Stephonalia seems to be in the shape of the tentacles. Whilst these are all quite 

 simple and uniform in the former, they are of two different kinds in the latter. A third 

 difference is found in the development of a large gonopalpon in each cormidium of 

 Stephonalia, whilst this seems to be rudimentary in Stephalia. Finally, the muscles 

 of the pneumatophore in the latter genus are equally disposed, whilst in Stephonalia 

 eight strong radial muscles and corresponding meridional constrictions are marked 

 regularly disposed at equal distances (PI. VI. fig. 33). 



Stephonalia bathyphysa, n. sp. (PI. VI.). 



Habitat. — South Pacific, west of Cook's Strait, New Zealand. Station 166, June 23, 

 1874 ; lat. 38° 50' S., long. 169° 20' E.; depth, 275 fathoms. 



Corm. — Two specimens of this interesting Auronect were found by me in the 

 Challenger collection, both rather well preserved, although very much contracted and 

 altered by the action of the alcohol. The first specimen (fig. 32, seen from the left side 

 in profile ; fig. 33, from the dorsal side) w r as pretty complete, and had a length of 

 20 mm., a breadth of 16 mm. The second specimen, somewhat larger, but incom- 

 plete, had lost the greater part of the nectosome as well as of the siphosome ; but 

 the upper third of the latter, with the corona of large-tentacled siphons, was better 

 preserved than in the first specimen ; its length was 24 mm., breadth 20 mm. (figs. 

 34-38). 



Nectosome. — The large, flatly spheroidal pneumatophore (figs. 32, 33, p) is 

 distinguished by an unusual development of the muscles in its thickened wall. Eight 



1 Stephonalia — Small marine corona, <m$ui/toi/, a*/o?. 



