92 THE ROYAL SOCIETY OF CANADA 
be taken for enlarged bases of the radial canals, because of 
their separate extension upward over the oral surface of 
the peduncle. And it is possible that they should be so interpreted. 
Since there is no fundamental distinction, other than gross anatomy, 
between canal and manubrium, this question can not be settled from 
the adult state; and unfortunately the manubrium is lacking in the 
smaller specimen. 
But, in any case, there is nothing, in Halimedusa, reminiscent of 
the so called ‘‘mesenteries’’ of Pandeids, e.g., Leuckartiara (Hartlaub, 
1913). 
The sexual products (both large specimens are apparently males) 
are evenly developed over the whole interradial surfaces of the manu- 
brium, including its four extensions over the peduncle, but the labial 
portion is bare of them (fig. 8). And there are no localized sexual 
ridges, or thickenings. In one specimen, it is true, the gastric wall 
is transversely folded (fig. 2) as noted above. But inasmuch as the 
folds are not alike in any two quadrants, and do not even follow any 
general plan, and since nothing of the sort is to be seen in the other 
specimen (fig. 8) equally advanced in sexual development, they are clearly 
the result of contraction, like the similar folds which so often charac- 
terize preserved specimens of Heterotiara anonyma (1913, p. 26). 
They are not comparable to the gonad folds of the Pandeide (Maas, 
1904, Bigelow 1909, Hartlaub 1913). Surface views indicate (fig. 8) 
that the sexual tissue is discontinuous along a narrow band in each 
perradius, as might be expected. 
The question whether the gonads are restricted to the walls of 
the manubrium, as in most Anthomedusae, or whether they extend to 
the basal parts of the radial canals, as in the Williide (Browne, 1896, 
Bigelow, 1909, Hartlaub 1914), depends, of course, on how we interpret 
the gastric lobes which extend over the peduncle. In the adult state 
these latter apparently belong to the manubrium, by the lack of any 
apparent demarcation, and especially by their voluminousness. But 
the possibility of the other interpretation, i.e., that they are in reality 
the bases of the radial canals, secondarily enlarged during the progress 
of the growth of the Medusa, makes me hesitate to postulate that 
the development of sexual products is sharply limited to the walls of 
the manubrium. 
Tentacles. The tentacles are divisible into two portions, the basal 
bulb and the terminal filament. Both-are hollow (fig. 7,), the latter 
smooth walled, without any rings or knobs; and the tip is simple, 
without swelling, knob or other nematocyst structure (fig. 3). The 
basal bulbs are circular in abaxial view and swollen (fig. 4): and, as 
side views show (fig. 5), they are situated at various levels above the 
