400 REPORT—1863. 
never included in a closed cavity, but is from the first directly exposed to 
the surrounding medium. In accordance with these views, M°Crady divides 
the gymnophthalmatous meduse into the “‘endostomata” and the “ exosto- 
mata.” 
While I think it highly probable that differences will be found in the de- 
tails of the development of the medusa-buds belonging to different species of 
the Hyprorpa, my own observations have not yet led me to adopt the above 
generalization of M°Crady. 
Formation of Buds by the Phanerocodonie Gonophore.—The phenomenon 
of budding does not necessarily find its extreme term in the formation of the 
gonophore. Many free-swimming medusz, some of which are known to have 
originated in hydroid trophosomes, complicate themselves by gemmation, 
which manifests itself in the production of othermedusa-buds upon various parts 
of their bodies. Among the examples of this phenomenon we may cite those 
which are seen in certain meduse of the type described by authors under the 
name of Sarsia, all of which probably originate in Coryne-like trophosomes. 
In these medusz, buds, which develope themselves into forms resembling that 
of the medusa which gives rise to them, spring from the manubrium or from 
the bulbous base of the tentacles. A fine example of the same phenomenon 
is afforded by the medusa of the tubularian hydroid, Hybocodon prolifer, Agass. 
In this beautiful animal, Agassiz* describes the base of the solitary tentacle 
which is continued from the distal extremity of one of the radiating canals of 
the medusa as itself producing a cluster of medusa-buds, which in time 
assume the form of the primary medusa, and may themselves repeat the same 
process, through the production of successive broods of similar buds, before 
they become detached as free natatory meduse. Steenstrup has observed 
buds which he regarded as sexually developed from the base of the tentacles 
in a medusa which he refers to his Coryne fritillaria, while Greene has de- 
scribed the production of buds, not only from the bulbous base of the tentacles, 
but along the course of the tentacles themselves, in his genus Diplonema. 
In the medusze belonging to the family of the Zginide—a group, however, 
of which we have as yet no positive proof of any of its members being derived 
from a polypoid trophosome, though neither is there any proof of the contrary 
—it is probable that multiplication by buds formed upon the inner surface 
of the stomach is a constant and normal phenomenon. It would further 
appear that these buds detach themselves while still in a very immature state, 
and that, after becoming free, they undergo a metamorphosis before arriving 
at their adult form. From the remarkable observations of Kolliker and of 
Fritz Miiller, referred to below (pp. 419, 420), it would seem indeed that there 
is here in some cases a heteromorphism, a difference of form being observed 
among successive broods of buds; but observations are still needed before we 
can arrive at any conclusion as to the ultimate destiny of these buds. 
Among the successive broods of medusze thus produced, whether by primary 
budding from the trophosome, or gonoblastidium, or by secondary budding 
from the primary one, there is, if we except certain instances just referred to 
among the Aginide, no heteromorphism ; and every medusa in the series is 
not only similar to every other, but is probably capable of direct sexual ma- 
turity. In certain other cases, however, it is different. This we have already 
seen in the medusiform zooids, to which we have above given the name of 
* gonoblastocheme.” In the medusa, for example, of Campanularia Johnstoni 
(fig. 17)—a medusa referable to the deep-belled section of the forms grouped 
together by Gegenbaur under the name of Hucope,—and in those of Laomedea 
* Op. cit. yol. iv. p. 245. pl. 24. 
