51 
as distinct from simple gemmation, show themselves, as is well 
known, under the condition of external buds, which are produced in 
various forms and in various positions on the animal. To these buds, 
which are truly sexual, being in some cases male and in some female, 
the author proposes to give the name of gonophore (yovog, tpo^sca). 
As an essential portion of the gonophore, we invariably find one 
or the other of two different kinds of bodies. One of these presents 
the form of a closed sac, in which a more or less disguised medusoid 
structure may in almost every instance be detected. For these 
bodies he proposes the name of sporosacs (Woga, duxxog). 
The other differs in no respect from a gymnophtlialmous medusa , 
and may conveniently be designated by this name. 
Both sporosacs and medusae contain the immediate products of 
the generative system, certain individuals of each producing ova, 
and certain others spermatozoa. 
In some cases the gonophore has only a single sporosac, or a 
single medusa, and these spring directly from the coenosarc of the 
zoophyte. In other cases these bodies are numerous, or, if single, do 
not spring directly from the coenosarc of the zoophyte, but from a 
special organ (blastostyle) to be presently described. In the former 
case, the gonophore may be called simple (Gonophora simplex ) ; 
in the latter, compound (G-onophora composita ). 
The simple gonophore consists essentially of a sac, which is a 
mere extension of the ectoderm of the zoophyte invested or not in- 
vested by a polypary, and containing within it in some cases a sporo- 
sac, in others a medusa. To this sac the author gives the name of 
ectotheque (sxrog, 
A correct notion of a compound gonophore may be best obtained 
by referring to some illustrative example such as that afforded by a 
Laomedea. 
In this genus the gonophores are produced near the axils of the 
ramuli in the form of oval hollow bodies or capsules, invested like 
the stems and ramuli by a distinct polypary. The axis of the cap- 
sule is traversed by an extension of the coenosarc of the branch in 
the form of a tubular column, from whose sides there bud forth in 
some cases numerous sporosacs, in other cases medusae, each with 
an ectothecal investment from the column. For this column the 
author proposes the name of blastostyle (/3Xa<mj, ffrvXog). 
In some cases (e.g. tubularia ) the compound gonophore is desti- 
