214 FAUNISTIC NOTES AT PLYMOUTH DURING 1893-4. 
radials develop later than the perradials, and that the lateral 
tentacles of each bundle develop later than the median tentacle, a 
stage is consequently passed through in which the perradial bundles 
consist of three tentacles and the interradials of only one. On the 
other hand, Margellium octopunctatum is defined by Haeckel as 
possessing perradial bundles of three tentacles and interradials of 
two tentacles—apparently on the sole basis of Forbes’ figure (loc. 
cit., pl. xii, fig. 3). In this definition Haeckel has disregarded 
Forbes’ statement that the number of tentacles in the interradial 
bundles is “either two or three, . . . the number varying in 
different specimens” (loc. cit., p. 65), and I am able to confirm 
Forbes fully in this respect. The development of the lateral 
tentacles in the interradial bundles takes place very irregularly. 
In some instances I have seen them arising together, one on each 
side of the median tentacle, and growing at a uniform rate ; but in 
the majority of cases there is an irregularity in the time of their 
origin, and one of the lateral tentacles may have become consider- 
ably developed before the rudiment of the other has appeared. It 
thus very often happens that individuals may be seen to possess 
interradial bundles of two tentacles only, and it is this condition 
which Forbes has figured. It is, however, as I have just shown, 
simply an instance of temporary asymmetry due to inequality of 
growth. The species Margelliwm octopunctatwm of Haeckel has con- 
sequently no existence. The oral tentacles (Mundgriffel) of our own 
specimens show a single bifurcation only (cf. Giard, Bull. Sci. France 
et Belgique, xix, 1888, pp. 317, 318, pl. xxi), whereas Haeckel gives 
“ Mundgriffel 3—4 mal dichotomisch getheilt”” as one of the 
characteristics of his species,—upon what grounds I do not know. 
The buds, so characteristic of this medusa, form a longitudinal row 
on each of the four sides of the manubrium, each row containing 
from two to four buds, which increase regularly in size from the 
oral to the umbrellar region of the manubrium. I have not detected 
the spiral arrangement attested by Giard, although his remarks on 
the order of their development apply equally well to the specimens 
I have examined. The medusa was taken in the tow-nets in 
February and March of this year also, but not in the same abund- 
ance as last year. It was succeeded towards the end of April by 
other Margelid medusa, Bougainvillea (Margelis), both principis and 
ramosa of Haeckel, which seem, indeed, to form only one species. 
Other Anthomeduse that have been taken are Corymorpha nutans, 
which was abundant in May this year; Sarsia prolifera and tubulosa 
(rarely), Podocoryne (Dysmorphosa) carnea, Tiara octona, Amphinema 
Titania (= Saphenia dinema of Forbes), and Amphicodon amphi- 
plewrus of Haeckel, ‘The last-mentioned very remarkable medusa 
