178 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Generic Characters (Polygastric generation = Sphæronectes). Polygastric 
Calyconecte with a single, rounded, edgeless, subspherical, swimming bell. 
There is a complete tubular hydroecium on the ventral side of the swimming 
bell, from the inner apex of which arises the long tubular hydrosoma. The 
groups of units are eudoxiform, and separated by free internodes. Each feed- 
es a single covering scale. 
ing polyp poss 
Generic Characters (Monogastric generation = Diplophysa). Monogastric 
Calyconectæ, representing a single group of units, consisting in a feeding 
polyp with tentacle and covering scale, and a fertile gonophore that serves also 
as a swimming bell. The covering scale is hemispherical, or subspherical, and 
possesses a simple ovate or cylindrical canal (phyllocyst) within its ventral 
axis. 
Spheronectes Köllikeri. — The swimming bell is about three quarters of a 
sphere in shape, and is about 10 mm, in diameter. The cavity of the bell is 
shallow; and there is a large and p@verful velum, by means of the movements 
of which the animal is enabled to swim. The bell possesses a circular canal, 
and 4 narrow, somewhat crooked, radial canals (r, 7, r, r, Fig. 51). These 
communicate, by means of the narrow duct (c), with the gastro-vascular cavity 
of the hydrosoma (h). There is a straight spindle-shaped vacuolated vesicle (f) 
buried within the gelatinous substance of the nectophore. The hydrosoma (4) 
arises from the inner end of a long, narrow invagination of the outer wall of 
the swimming bell (the hydræcium). The order of appearance of the various 
organules upon the hydrosoma is shown in Figure 52, The first to develop 
are the feeding polyps (p); then follow, in order, the tentacles (1), the cover- 
ing scale (c. s.), and gonophore (g). The hydrosoma attains a length of about 
50 mm., and there are numerous groups of units (cormidia) separated hy free 
internodes. One of these groups of units that has very recently become sepa- 
rated from the hydrosoma, and is therefore in the Diplophysa stage, is repre- 
sented, highly magnified, in Plate 17, Figure 53. 
Diplophysa Köllikeri (Plate 17, Fig. 53). — This is merely the free Mono- 
gastric or Eudoxia form of Sphæronectes Köllikeri, and consists of a single 
group of units that has become separated from the hydrosoma of the latter 
animal, and leads an independent existence. The covering scale (o. s.) is thick 
and hemispherical in shape. It contains a simple ovate canal or phyllocyst 
(phe.). There is a single feeding polyp (p), a single tentacle (1), and a gono- 
phore (g). The tentacle gives rise to many small filamentous side branches, 
which terminate in nematocystic bulbs. The gonophore serves also as a swim- 
ming bell, and its manubrium will become much larger than is shown in 
Figure 58, and will contain the genital products. The tube ad. is the means 
by which the animal was once attached to the hydrosoma of S. Köllikeri. This 
tube soon atrophies. The entoderm of the feeding polyps of the manubrium 
of the gonophore and of the nematocystic bulbs of the tentacles is rich yellow 
or orange. This animal, in the Sphæronectes stage, was met with in various 
places among the Fiji Islands. Our drawings are derived from a specimen 
found upon the surface of Suva Harbor, December 12, 1897. 
