ON THE REPRODUCTIVE SYSTEM IN THE HYDROIDA. 377 
The contents of the gonophore are either ova or spermatozoa, and the 
sexes are invariably found separated on distinct colonies. The ova, while 
contained within the gonophore, pass through the various stages of develop- 
ment up to that of ciliated embryos, in which state, as has been already 
shown by Lovén, they are discharged into the surrounding water through 
the orifice in the summit. 
If we follow the development of these extracapsular gonophores, we shall 
find (d, ¢), as indeed Lovén had already pointed out, that they are originally 
produced within the gonangium where they originate, exactly like ordinary 
intracapsular gonophores, as buds from the blastostyle. By the growth of 
the blastostyle the gonophores are carried upwards with it, in the order of 
their maturity,—the oldest ones, while within the gonangium, being always 
_ nearest the summit of the blastostyle ; but instead of discharging their con- 
tents and then withering away on their arrival at the summit of the gonan- 
gium, as in ordinary adelocodonic forms, they are here carried out through 
the summit, become truly extracapsular, and in this state undergo, with their 
contents, further development, while the growing blastostyle always keeps 
its extremity truncated on a level with the gonangium, whose orifice it con- 
tinues to close by a plug-like expansion, which at the same time affords a 
support for the gonophores after they have become extracapsular. Two or 
three of these extracapsular gonophores, in different stages of development, 
may be usually seen, borne each by a short peduncle upon the opercular 
summit of the blastostyle, with whose cavity that of their spadix freely com- 
municates through the tubular axis of the peduncle. 
While the gonophore is still contained within the gonangium, the meso- 
theca has become developed in it, and the rudimental tentacles (f) may be seen 
thrown back upon its walls in the form of a little star, while the whole is 
confined in the investing ectotheca. 
That the bodies now described belong to the class of adelocodonic rather 
than to that of phanerocodonic gonophores must, I think, be admitted. In 
all essential points, except in the presence of tentacles developed from the 
mesotheca, they agree with the gonophores of Tubularia indivisa, which 
must certainly be classed among the adelocodonic forms, notwithstanding 
their possession of a well-developed mesotheca and gastrovascular canals. In 
both the aperture of the mesotheca is reduced to a mere perforation, and in 
neither is the mesotheca ever developed as a locomotive organ. 
It must also be borne in mind, that when true phanerocodonic gonophores 
are produced in Laomedea and other Campanularide, they belong in almost 
every instance to the type in which the generative elements are not produced 
directly, as in this case, between the ectoderm and endoderm of the manu- 
brium, but are formed in special zooids developed from some part of the gas- 
trovascular system ; Laomedea tenuis, Allm.*, and, according to an observation 
of A. Agassiz +, Lafwa cornuta, Lamx., affording the only known exceptions 
_to this rule. 
The extracapsular gonophores of Laomedea Lovéni are thus of no little 
interest in the morphology of the Hyprorpa, and it will be found convenient 
to speak of them under a special name. Their resemblance to a pomegranate, 
or perhaps still more obviously to a poppy-capsule, with its sessile stellate 
stigma, will instantly strike us; and itis this comparison which has suggested 
to me the name of “ meconidium” +t, by which I have elsewhere found it useful 
to designate them. 
* “Notes on the Hydroid Zoophytes,” Ann. Nat. Hist., Nov.1859. + Agass. op.cit.p. 351. 
{ A diminutive noun, formed from pjxwr, a poppy. “ Notes on the Hydroid Zoophytes,” 
Ann. Nat. Hist., August 1859. 
