242 



THE VOYAGE OF H.M.S. CHALLENGER. 



the base of each palpon is always a simple thin tasting filament, richly provided with 

 small cnidocysts and cynidocils. 



Gonodendra. — The corms of all Forskalidse seem to be monoecious ; the cormidia are 

 usually monoclinic ; ,but in Bathyphysa perhaps diclinic. The gonodendra are distylic, 

 either male or female, in Bathyphysa and Strobalia, whilst they are monostylic in 

 Forskalia and Forskaliopsis. Each cormidium usually possesses in these two typical 

 genera a single pediculate gonodendron, which arises separately from the siphon and 

 cyston, and bears upon a common pedicle a spindle-shaped sexual palpon (PI. X. fig. 21) 

 and numerous roundish gynophores in the proximal part, oblongish androphores in the 

 distal part. Each female gonophore (/) develops only a single large ovum, each male 

 a large club-shaped spermarium (h). In some species two sexual palpons (" twin- 

 tasters "), more rarely three or four, are attached to the base of the hermaphroditic 

 gonodendron. There seems to be some variety in this arrangement. Strobalia differs 

 in the possession of two separate clustered gonodendra, a male and a female, both 

 arising separately from the common base of the ordinate cormidium. 



Synopsis of the Genera of Forskalidse. 



Nectosome without palpons. 



Trunk of the siphosome articulate, with - 

 regular equidistant annular constric- 

 tions. 



Nectosome with palpons between the 



nectophores. 

 Trunk of the siphosome not articulate,  



without regular annular constric 



tions. 



Cormidia ordinate. Gonodendra distylic, arising 

 from the base of the siphonal pedicles, 



Cormidia loose. Gonodendra monostylic, alter- 

 nating with the siphonal pedicles, 



Cormidia loose. Gonodendra monostylic, be- 

 tween the siphons, which have hepatic ridges 

 (no villi), ..... 



Cormidia loose. Gonodendra distylic, between 

 the siphons, which have hepatic villi (no 

 ridges), ..... 



50. Strobalia. 



51. Forskalia. 



52. Forskaliopsis. 



53. Bathyphysa. 



Genus 50. Strobalia, 1 Haeckel, 1888. 



Strobalia, Hkl., System der Siphonophoren, p. 42. 



Definition. — Forskalidse with ordinate cormidia, and segmented trunk of the sipho- 

 some. Gonodendra distylic, arising from the base of the siphonal pedicles. Siphons 

 with hepatic ridges. Nectosome without palpons. 



The genus Strobalia comprises some new species of Forskalidse, which are very 

 similar in general appearance to some smaller forms of the true Forskalia, but differ 

 from it in two important points. The cormidia are perfectly ordinate, not loose ; 

 and the gonodendra are gonochoristic or distylic. Each cormidium of the siphosome is 

 composed of five different medusomes, three of which are sterile (a siphonal, a cystonal, 

 and a palponal) and two fertile (a male and a female). Each of the three sterile 



1 Strobalia = Marine spiral, ot{o/3oj, ahtos. 



