REPORT ON THE SIPHONOPHOR^. 149 



jelly mass of the apical and ventral half of the nectophore. The odd dorsal canal (cd) 

 runs along the convexity of its basal and dorsal half. The two paired lateral canals (ex 

 right, cl left) pass into the two lateral lobes or buccal valves of the helmet-shaped bract. 

 The blind ends of all four canals are somewhat swollen and club-shaped. Their course, 

 as well as the mode of their apical junction, are very variable, and subject to many 

 individual abnormahties. Usually the ventral canal is shorter than the dorsal, and the 

 right shorter than the left. 



Siphons (PL XXXI. fig. 1 ; PI. XXXII. fig. 8, s; fig. 11).— The siphon or polypite, 

 which is attached to the stem at the lateral incision of each bract by a very short pedicle, 

 exhibits a hemispherical basigaster (sb), the thick wall of which is filled up by cnidoblasts. 

 The stomach (sh) is ovate and exhibits eight broad yellow hepatic stria? (sh). The con- 

 tractile proboscis (sr) is very muscular and opens through a mouth of very variable form 

 (so). Sometimes the distal part of the siphon is so invaginated and retracted into the 

 proximal part, that it assumes the peculiar form shown in fig. 11. 



Tentacles (fig. 8, t ; figs. 12-14). — The tentacle, which depends from the short pedicle 

 of each siphon, is very long and mobile, cylindrical and distinctly articulated, beset with 

 a series of very numerous tentilla or lateral branches. These arise from the constrictions 

 between each two segments of the tentacle. Each tentillum (figs. 12-14) contains a 

 canal, which is somewhat convoluted before entering into the dilated cnidosac (fig. 13). 

 The latter is reniform or crescentic and contains a strong battery of cnidocysts, six to 

 eight longitudinal rows of small medial paliform cnidoblasts (km), and on each side (right 

 and left) a longitudinal series of large sabre-shaped lateral cnidoblasts (kl), eighteen to 

 twenty-four in each series. Three groups of small pyriform thread-cells (an odd dorsal, 

 hp u and two paired ventral, kp u ), are found on the base and on both sides of the distal 

 end of the battery. The terminal filament of the tentillum (tf) forms in the contracted 

 state three coiled spiral turnings. 



Gonophores (fig. 8, h ; fig. 10). — Each cormidium usually exhibits, half hidden under 

 the bract, a single gonophore, either male or female. It is placed at the ventral side of 

 the siphon, whilst the tentacle arises from its dorsal side. The umbrella of the gonophore 

 (fig. 10) is laterally compressed, bilateral, and exhibits two very broad wings in the 

 sagittal plane ; the dorsal wing (nd) is triangular and nearly as large as the nectosac, 

 whilst the ventral wing (nv) is much smaller. The nectosac (w) is hemispherical or 

 campanulate, with a broad velum (v). The peduncular canal enters between the 

 two wings into the jelly umbrella and gives off at the apex of the nectosac the four radial 

 canals (cd dorsal, cv ventral, ex right, cl left). The spindle-shaped spermarium (fig. 8, h) 

 and the ovate or subspherical ovarium (fig. 10,/) are rather small, and in the largest 

 Eudoxiae only fill the superior half of the subumbrellar cavity. 



