REPORT ON THE SIPHONOPHOR^I. 267 



enidoband, and here are visible in younger tentilla the rudiments of the tripartite terminal 

 filament. This Las disappeared in the adult tentillum (fig. 14). The cnidosac of this latter 

 is convex on the dorsal, concave on the ventral side, and bearsnear its middle zone a pair 

 of lateral purple pigment-rings, like ocelli, similar to those which I have described in 

 Physophora magnified (84, pi. iv. fig. 28). These ocelli (fig. 14, ty), like the similar 

 oeellar spots of many other animals, are probably protective ornaments discouraging and 

 frightening the attacking enemies. 



Palpons (PL XIX. fig. 1, q ; PL XX. fig. 16, q). — Immediately beyond the nectosome 

 is expanded the large corona of palpons, wbich arises from the top of the siphosome. This 

 corona is simple in Discolabe (as also in Stephanospira), whilst it is double in Physophora. 

 Each cormidium bears only a single taster, attached to its uppermost or proximal part. 

 It is rose coloured, violet towards the apex. The fully-expanded palpon is a tliick-walled, 

 very firm, cylindrical or spindle-shaped tube 30 to 40 mm. in length and 6 to 8 mm. 

 in breadth ; in the contracted state it is scarcely half as long, and pyriform. The thick 

 muscular wall is supported by a strong cartilaginous fulcrum and surrounds a wide 

 cavity, which is closed at the pointed distal end ; this is provided with a corona of twenty 

 to thirty very large cnidocysts, the protruded cnidofilament of which is more than 1 mm. 

 in length. The proximal base of the palpon is obliquely truncated and apposed to 

 the articular facette of the trunk by a very small pedicle. The narrow canal of the 

 pedicle, which connects the wide cavities of the trunk and the palpon, is visible after the 

 detachment of the latter as a small pore in the centre of the facette (figs. 9-13, cq). 



Palpacles (PL XIX. fig. 1, r). — Each palpon bears attached to its proximal base, in the 

 middle of its upper face, a very long and thin tasting filament. It may be extended 

 to a length which surpasses that of the palpons three or four times or more. The thin 

 wall of the cylindrical tubule is distinctly segmented, with very numerous equidistant 

 annular constrictions (PL XX. fig. 16, r). 



Gonostyles (PL XX. figs. 9-16, g). — Each cormidium possesses two gonostyles, arising 

 from the periphery of the vesicular trunk, one very near to the other, between siphon and 

 palpon. The female gonostyle is an ovate, richly branched bunch (gf), composed of many 

 hundred small gynojmores. These are subspherical, pediculate, and contain a single ovum 

 only. The male gonostyle is very different in form, not branched, but a long cylindrical 

 tube with wide cavity and thin muscular wall, which can be widely extended or strongly 

 contracted. The surface of this gonopalpon (gq) is covered with numerous oblongish, 

 spindle-shaped, or subcylindrical androphores, the size and age of which increases from 

 the proximal towards the tapering distal end. When the ripe androphores in the latter 

 are detached, their short pedicles remain as small hemispherical papillae. Older gono- 

 styles bear only a few androphores at their proximal base, while the greater part of the 

 naked tube hangs down like a papillate tentacle (fig. 16, lip). The ripe androphore is 

 about four times as long as broad, and much larger than the ripe gynophore. 



