SPECIES OF CEPHALODISCUS. 9 



even sunk below the general surface ; spines long, not very obviously related 

 to the ostia ; width of spines about 5 mm. Polypides colourless ; all known 

 individuals are female. Front of buccal shield to end of visceral mass 1 • 5 mm. 

 Plumes six pairs, axis of each terminating in an end bulb with refractive 

 colourless beads. Stolon not so long as the rest of the polypide in the contracted 

 condition, commonly directed towards the mouth. Buds, one or two, rarely 

 three. Free ova -33 mm. across. 



Species hodgsoni. Material. Eight specimens dredged by the ' Discovery ' 

 in the Antarctic Ocean in 1902-3, in 100 to 300 fathoms. New species. 

 Tubarium. Colony irregularly and closely liranched (fig. 1, plate 2) ; distance 



Text-Figure 5.—Cep}ialodiscus gracilis, portion of a colony (x 5). The dark bodies are the polypides and 

 embryos. The cavity of the tubarium is continuous, and opens by numerous ostia. (Copied from Harmer, 

 10, plate 2, fig. 15.) 



from one l)raiich to the next about 10 mm. ; width of branch aljout 6 mm. ; 

 cavity of tu])arium with inner surface smooth ; ostia oval, 3*3 by 2' 3 mm., with 

 four or five long, radiating spines, simple or forked ; width of spines • 6 to 1 mm. 

 Polypides colourless ; males, females, and hermaphrodites (one ovary and one 

 testis), indistinguishable externally ; front of buccal shield to end of visceral mass 

 2 mm. Plumes six pairs, axis of each terminating in an end bulb, with refractive 

 colourless beads. Stolon curved forwards or backwards, average length in 

 contracted state 2 mm. or less. Buds two, sometimes three or four. Free ova 

 •45 mm. across. 



Species gracilis. Material. One specimen, obtained at Station 89 of the 

 ' Siboga ' Expedition, East Coast of Borneo, on reef, between tide-marks. 



