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



cystous (with a terminal mouth), whilst they seem to be mouthless in Halistemma. 

 Besides the oldest known form, the Australian Cnpulita boivdichii, the following species 

 probably belong to this genus: — (1) Nanomia cara, A. Ag. (North-west Atlantic, 

 37, p. 200); (2) Anthemodes canariensis, Haeckel (North-east Atlantic, 38, p. 140, 

 Taf. i.) ; (3) Agalmopsis fragilis, Fewkes (Tropical Atlantic, 44, pi. v. fig. 2) ; (4) Agal- 

 mopsis elegans, Sars, partim! (North Atlantic, 27, Heft i. Taf. v.); (5) Halistemma 

 pictum, MetschnikofT, described in 1871 in the Eussian language, Mediterranean) ; (6) 

 Halistemma tergestinum, Claus (Adria, 74, Taf. i.-v.). 



Genus 48. Agalmopsis, 1 Sars, 1846. 

 Agalmopsis, Sars, Fauna littoralis Norvegia;, Heft i. p. 31, taf. v., vi. 



Definition. — Agalmidse with a long and movable siphosome, the trunk of which is 

 very contractile ; bracts with large intervals. Cormidia loose ; palpons and gono- 

 styles on the internodes scattered between the siphons. Tentilla tricornuate, with a 

 terminal ampulla and two paired horns. 



The genus Agalmopsis was described very accurately by Sars in 1846, and illustrated 

 by excellent figures. The North Atlantic Agalmidse, however, which are repre- 

 sented in his pis. v. and vi., belong to two (or even three?) different genera. The 

 first form, figured in pi. v., has simple terminal filaments of the tentilla, and belongs 

 therefore to the preceding genus Cupidita. The second form, represented in pi. vi., 

 has tricornuate tentilla, with an odd terminal vesicle and two paired lateral horns. This 

 form may retain the original name Agalmopsis elegans, and represent the type of this 

 genus. Closely allied to it is the North American Agalmopsis catena, described by 

 Fewkes as Agalma elegans (43, viii. pis. ix., x.). A different species, Agalmopsis 

 dissoluta, Hkl., inhabits the Tropical Atlantic. A fourth species is the Mediterranean 

 Agalmopsis sarsii, accurately described by Kolliker (4, p. 10, Tab. iii.). 



Genus 49. Lyehnagalma, 2 Haeckel, 1881. 



LycJuiagalma, Hkl., MS. Ind., and System der Siphonophoren, p. 40. 



Definition. — Agalmidae with a long and movable siphosome, the trunk of which is 

 very contractile ; bracts with large intervals. Cormidia loose ; palpons and gono- 

 styles on the internodes scattered between the siphons. Tentilla multicornuate, with 

 a terminal ampulla and a corona of eight radial horns. 



The genus Lychnagalma was established by me for a most elegant small Agalmid, 

 a complete specimen of which I had captured in December 1881, during my residence in 



1 Agalmopsis = Similar to an Agalma ; Ayahfix, Stpi;. 2 Lychimijalma = Candelabra ornament, Tui^i/of, dya^/ia. 



