2S0 THE VOYAGE OF H.M.S. CHALLENGER. 



its ventral median line (fig. 9, is), bisected it so regularly that the cormidia were ordinate 

 symmetrically right and left. 



Siphons (figs. 7-9, s). — The size of the polypites, according to the ordinate bilateral 

 arrangement just mentioned, increases from the ventral towards the dorsal side (fig. 8, s)- 

 They were ovate thick-walled sacs, strongly contracted in the only spirit specimen observed. 

 The structure of the siphons is probably the same as in Athorybia (PI. XII. fig. 10). 



Tentacles. — The greatest part of the tentacles were detached and lost in the spirit 

 specimen observed ; a few fragments only remained. The tentilla were of two kinds, and 

 apparently both of the same form as described and figured by Fewkes in his Athorybia 

 formosa (loc. cit., p. 274, pi. vi. figs. 7-10). The smaller and more frequent form of 

 cnidosacs is similar to that figured in Athorybia ocellata (PI. XII. figs. 11-13). The 

 larger and rarer form exhibits besides two large dorsal dendritic appendages, which 

 were dichotomously branched, of the same shape as in Anthophysa formosa (Fewkes, loc. 

 cit., fig. 7, lateral view, from the right side, fig. 8, basal view). 



Palpons (figs. 7-9, g). — The tasters were very large and numerous in the specimen 

 observed, and composed a multiple corona beyond the corona of bracts. Their form is 

 slender, spindle-shaped, tapering towards the attached basal and the closed distal ends. 



Gonop>hores (g). — Close to the base of each siphon are attached to the siphosome two 

 small branched gonodendra, a male and a female. Their structure is similar to that of 

 Athorybia (PL XII.), the spermaria (fig. 17) as well as the ovaria (fig. 18). 



LATER ADDITION TO THE ANTHOPHYSID^E. 



Plosophysa agassizii, Fewkes. 



Ploeophysa agassizii, Fewkes, Arm. and Mag. Nat. Hist., ser. 6, vol. i. pp. 317-322, pi. xvii., 

 1888. 



AVhile correcting the proof of this sheet, I have received a paper by Mr. J. Walter 

 Fewkes, published in May 1888 (loc. cit.), and entitled : On a New Physophore, Plceophysa, 

 and its Relationships to other Siphonophores. A comparison of the two figures repre- 

 senting it (drawn from two small spirit specimens from the Gulf Stream, found in a bottle 

 from the "Albatross " Expedition, 1886), and of my figures of Anthophysa darwinii 

 (PI. XII. figs. 8, 9, printed in 1887), informs us that these two Anthophysidse are very 

 closely allied, or perhaps identical. Plosophysa of Fewkes is an Anthophysid (either 

 Athorybia or Anthophysa) which has lost its bracts, and the pneumatophore of which, 

 highly retracted, is embraced on the ventral side by the prominent cucullate nectostyle. 

 Fewkes calls this lamellar cowl-shaped nectostyle the hood, "and supposes it to be a new 

 organ, elsewhere unknown among Physophores in this form " (p. 318). He even regards 

 Plceophysa as the type of a new family — Plceophysidaj (p. 320). 



