REPORT ON THE SIPHONOPHOR^E. 



273 



differences similar to those in the Agalmidse. The cnidonode of the tentillum includes 

 a spiral band with a few turnings ; the cnidobattery of this band is composed of very 

 numerous small median cnidocysts and two opposite lateral rows of large spindle -shaped 

 cnidocysts. It bears a simple terminal filament in the two genera Rhodophysa and Melo- 

 physa, whilst it is trifid in the two genera Athorybia and Anthophysa, divided into a 

 median terminal vesicle and two paired lateral horns ; usually these are coiled up spirally 

 (PI. XII. figs. 11-13). The distal part of the cnidonode is prolonged commonly on the 

 dorsal side into a conical apophysis or a solid pointed spur, composed of large hyaline 

 entoderm cells. Besides, the genus Anthophysa is distinguished by the possession of 

 a second, larger and rarer, kind of cnidonode, differing from the former in the develop- 

 ment of two paired, dendritic or palmate apophyses on the dorsal side of the cnidosac. 



Gonostyles. — Each cormidium of the siphosome (probably in all Anthophysidse) is 

 monoclinic and bears two gonodendra, a male and a female, attached to the base of the trunk, 

 near to the insertion of the appertaiuing siphon. Sometimes the two branched gonostyles 

 arise separately, each with a proper pedicle (PL XII. fig. 17, gp, male ; fig. 18, gp, female) ; 

 at other times both arise from a common pedicle, which also bears some small palpons 

 or sexual hydrocysts (9, pi. ix. fig. 12). The gonophores arise clustered in variable 

 number from the branches of the dendritic gonostyles ; the males are usually coloured 

 (reddish or white), the females colourless. 



The androphores, or the male medusiform gonophores (fig. 17, h), have an oblong, 

 club-shaped or even cylindrical umbrella, the narrow distal mouth of which is surrounded 

 by a small velum ; above this lies a small circular canal, which unites the four radial 

 canals. The spermarium (lis) is a long spindle-shaped or cylindrical manubrium, with a 

 central spadix (hx) ; it fills up the subumbrellar cavity and is often protruded from it. 



The gynophores, or the female medusoid gonophores (fig. 18,/), develop only a single 

 large ovule in the wall of the manubrium, and the central canal of the latter, growing 

 around the surface of the ovule, and partly obliterating, forms a network of irregular, 

 spadicine canals, not to be confounded with the four radial canals of the embracing 

 umbrella. 



Synopsis of the Genera of Anihophysidse. 



Tentilla with a simple (naked or involucrate) 

 cnidoband and a single terminal filament. 



Tentilla with an involucrate cnidoband and 

 three to five terminal appendages. Bracts 

 without nectosac. 



Bracts with a rudimentary nectosac at the 



distal end. Cnidoband naked, . 58. Rhodophysa. 



Bracts without nectosac. 

 volucrate, 



Cnidoband in- 



All tentilla of the same form, tricornuate. 

 Cnidosac without dendritic apophyses, . 



Tentilla tricornuate, of two different forms ; 

 the larger with two dendritic apophyses 



of the cnidosac, 



(ZOOL. CHALL. EXP. — PART LXXVII. 1888.) 



59. Melojihysa. 



60. Athoryhia. 



61. Anthophysa. 

 lllihh 35 



