96 
CHARLES L. BOTJLENGER. 
About this time the velum becomes perforated in its centre, 
the four primary tentacles stand stiffly out, and each medusa, 
although still not fully formed and attached to the parental 
manubrium, pulsates with great vigour/’ 
From the above accouuts we see that the early development 
of the buds in this medusa is of a quite peculiar type, and 
Gunther in 1894 remarked: “The method of invagination of the 
ectoderm to form the entocodon or f Glockenkern 9 in Lim- 
nocnida differs from the method of formation in most other 
medusae, in which the process has been described, and I am 
inclined to think that in this respect Limnocnida exhibits 
a more primitive condition.” 
Since that time our knowledge of the bud-formation in the 
Hydromedusae has been completely revolutionised by Goette’s 
monograph on the subject (6). He showed that, at any rate 
in all the forms he was able to examine, no double-walled cup 
of endoderm is present, even in the youngest stages, and that 
the four radial canals arise from four separate pouches of 
endoderm which grow out simultaneously fj*om the cavity of 
the early bud. His results have been confirmed by J. Hadzi 
(12) for Hydroids, by W. Richter (13) for the Siphonophora, 
and by myself (5) for the Egyptian Hydromedusan Moerisia 
lyonsi. 
Goette’s discovery has not only shattered the generally 
accepted views on the development of the medusa-buds in the 
Hydromedusae, but has also led to considerable alterations in 
the existing theories on the relation between medusoid and 
hydroid individuals. I have, for this reason, carefully 
re-investigated the development of the buds of Limno- 
cnida, not only with a view to clearing up the discrepancies 
between the accounts of Gunther and Moore, but also in the 
hope of throwing fresh light on the subject of bud-formation 
in the Hydromedusae generally. 
My observations on the earliest stages in the formation of 
the buds of Limnocnida agree with those of previous 
authors ; the ectoderm of the hollow two-layered bud invagi- 
nates into the endoderm to form the hollow entocodon, which 
