REPORT ON THE SIPHONOPHOR^E. 227 



apical or proximal side. The two lateral sides (right and left) are irregularly triangular, 

 with a prolonged proximal apex. The convex dorsal and the concave ventral faces are 

 bilaterally symmetrical and nearly hexagonal ; the two lateral edges of each hexagon are 

 slightly convex ; the two basal (or distal) edges are separated by the small ostium of 

 the nectosac, and the two apical (or proximal) edges by the deep axial incision which 

 embraces the stem. The two lateral horns or auricles, separated by the latter, are 

 nearly rhombic. The thickness of the wedge-shaped nectophore increases gradually from 

 the proximal apex towards the distal base, which is bilaterally truncated. In the 

 median line of the concave ventral side of the nectophore arises the short triangular 

 pedicle which attaches it to the stem. 



Nectosac (figs. 8, 9, w). — The subumbrellar cavity of the nectophore is small and 

 occupies only the middle part of its distal or basal half. It is oblongish in the profile 

 view (fig. 8), bicornuate in the dorsal view (fig. 9). The two symmetrical apical horns 

 are rounded. The basal mouth of the nectosac is narrow, and provided with three 

 scarlet ocelli or pigment-spots at the base of the velum, just on the three points where 

 three radial canals (the dorsal and the two lateral) inosculate into the marginal ring- 

 canal. The fourth (ventral) canal possesses no ocellus. The course of the four radial 

 canals is as usual (compare above, p. 216). 



Siphosome (fig. 8, lower half). — The trunk of the siphosome is of about the same 

 length as that of the nectosome, and densely covered with very thick and large bracts, 

 which can recede only very little one from another, and permit, therefore, no consider- 

 able extension and shortening of the siphosome. This is almost globular, of 50 mm. 

 diameter. The bracts are so arranged that the subspherical outside of the siphosome 

 is completely loricated by the convex urticating abaxial face of the cartilaginous covering 

 scales ; these compose a continuous spiral, which is dexiotropic and ascends around the 

 undulating axial trunk in four to six complete turnings. The trunk forms the axis of 

 a subcylindrical or slenderly conical hydrcecium, i.e., a cavity which serves for the 

 reception of the contracted and retiring cormidia ; this protective cavity is closed around 

 by the carapace of the covering scales, and open only at the dilated distal end, whence 

 the siphons and tentacles can proceed (fig. 8, s). 



Cormidia. — The polymorphous persons which compose the siphosome, siphons, 

 palpons, and gonostyles arise scattered and separately from the common trunk ; I was 

 however, not able, in the single specimen observed, to determine with full certainty 

 their peculiar arrangement, and the true composition of the loose cormidia. It 

 seemed to me that about half a dozen (or perhaps eight) siphons and tentacles arose 

 from the lower or distal half of the trunk of the siphosome, intermingled with a number 

 of palpons ; whilst distylic gonodendra, male and female separately, were attached to its 

 upper or proximal half, together with numerous palpons and palpacles, which were 

 protruded between the scales. Unfortunately most of the appendages were detached 



