SECTION IV, 1916 [91] “TRANS. RSC: 
Halimedusa, a New Genus of Anthomedusæ 
By Henry B. BIGELOW 
Presented by J. PLAYFAIR McMurricx, F.R.S.C. 
(Read May Meeting, 1916) 
Halimedusa typus, gen. nov., sp. nov. 
Three specimens, taken off Amphitrite Point, Vancouver I.; 
surface, September 12, 1914; respectively 16, 16 and 10 mm. high. 
Thespecimen selected as the type (PI. I., fig. 1) is16mm. high, by 13mm. 
in diameter, the bell thick walled, especially at the apex, its cavity 
about 3 of the bell height. 
The manubrium is situated on a broad, low, peduncle (fig. 2) 
which, anatomically, is a simple gelatinous prominence, without any 
trace of the peculiar vacuolated structure which characterizes the genus 
Turritopsis. The radial and circular canals are narrow and smooth 
walled (fig. 3): 1.e., without any of the diverticula so common among 
Pandeids. (1909, Hartlaub 1913). 
The manubrium and gonads, and the tentacles, are the most 
interesting and characteristic features of this new genus. In both 
the large specimens the manubrium is divisible into gastric and labial 
portions. The latter (fig. 8), is cruciform in cross section, resulting 
in four apparent lips. But the oral margin is entire, i.e., not sub- 
divided or incised, the lips being merely the result of the longitudinal 
radial folding of the oral end of the manubrium as a whole, thus not 
comparable to the lip lobes of many Leptomedusæ. The entire oral 
margin is closely studded with a single row of small, roughly spherical, 
nematocyst knobs (fig. 6), which are either immediately sessile on the 
actual margin of the lip, or provided with very short stalks, according 
to their state of contraction. 
The relatively large gastric portion of the manubrium is likewise 
strongly cruciform in cross section: and its four radial folds clasp the 
peduncle, like so many expanded sinuses, to merge suddenly, at the 
base of the latter, into the narrow radial canals. 
In the type specimen the lower part of the manubrium is irregular- 
ly folded and twisted transversely (fig. 2): but in the other adult 
individual it is smooth except for the primary radial plications (fig. 8). 
At first sight the basal part of the four radial gastric folds might 
