526 
CCELEKTERATA. 
youDg Medusa is still very small and undeveloped, a blastostyle is pro- 
duced from its aboral surface, and at least two 0«mm-buds are developed 
on it ; it is only after having got rid of this gemmiparous propensity 
that the temporarily arrested evolution is continued, and the characters 
of the adult Cunina acquired. The author (1. c. pp. 27-36, pi. v.) doubts 
if the young of Cunina rhododactyla wore found by Hackel 
in the stomach of Geryonia hastata ; they probably belonged to some 
other species of Cunina— a. question which materially affects Hackel’s 
theory. 
According to Du Plessis (12), the same species of which in 
winter produces true Medusae, through gemmation from the axis of the 
gonophore, will in summer afford another kind of sexual reproduction, 
the gonophores being at this time themselves either male or female, 
according to the colonies, and containing either spermatozoa or eggs, or 
planuliform embryos. 
‘Eimer’s (7) experiments demonstrate that the contractions of the disc 
in the Discophora originate in a narroAV band fringing each of the eight 
marginal incisions, in which the “ marginal corpuscles ” are situated, and 
spread from these to all other parts of the disc. (Analogous obser- 
vations on Slabberia conica, by G. J. Romanes, Nature, xi. p. 29.) The 
facts cannot bo explained by the hypothetical presence of one or two 
nerve rings, but only by numerous nervous fibrils traversing the gela- 
tinous substance in various directions, as in Beroe [Zool. Rec. x. p. 515]; 
their presence will be demonstrated in a future paper. The movements 
of the Medusa, though involuntary, are nevertheless under the influence 
of the will, as are the respiratory movements in higher types ; in fact, 
their primary function is respiration, though they also discharge those 
of circulation and nutrition, the contractile zones mentioned above, and 
the adjoining parts of tho gastrovascular system, acting as nutritive 
pumps. 
H. Fol has communicated an abstract of his paper on the egg of Gery- 
onia [Zool. Rec. X. p. 611] to Arch. Z. exper. iii. pp. xvii.-xix., not satis- 
fied with that which appeared in J. Zool. iii. pp. 154-158, pi. iii. An 
account of Kleii^enbeiig’s “ Researches on the anatomy and develop- 
ment of Hydra, is given in Q. J. Micr. Sc. xiv. pp. 1-18. 
The knowledge of the earliest stages of Siphonopliora (Epibulia au- 
rantiaca, Agalma sarsi, llalistemma rubrum, Ilippopodius gleba, Stepha- 
nomia pictum, &c.), is. considerably advanced by Metschnikoff's studies 
(11, pp. 35-37, pis. vi.-xii.), which are the more reliable, as he was able 
to trace the evolution of several species from the ovum, without being 
restricted to the observation of the free swimming young ones. He 
opposes the current “ polymorphic " theory of the Siphonophora, without 
however bringing forward any decisive argument against it, and con- 
cludes with a very suggestive comparison of the Ctenophora and larval 
Echinoderms. 
Local Lists, Faunas, 
Allmann (1) reports upon the deep-sea Ilydrozoa collected in tlie 
