488 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
a relation to the Edwardsise. In both there are only eight complete 
septa; both have, in the body an ectodermal nervous and muscular 
layer and both want acontia. On the other hand there is a difference 
between the two groups in the development of the ciliated bands of the 
mesenterial filaments ; for in Edwardsia earned they are very well 
developed, while in Protanthea they are wanting. Enquiry must still 
be made as to the conditions that obtain in other species of Edwardsia. 
The development of a parietobasilar muscle in the Protanthese agrees 
with their sedentary mode of life ; it is wanting in E. earned. 
Norwegian Pennatulida.* — Mr. J. A. Greig gives a list, with his- 
torical and bibliographical prefaces, of the Pennatulida of Norway ; 
twenty-nine species are recognized in it, and synonymical and other notes 
are generally given. 
Organs of Relation of Hydromedusse.f — Dr. M. Chapeaux has made 
an attempt to reconcile the very divergent views of authors with regard 
to these organs. From his experiments on the fresh- water Hydra he 
comes to the conclusion that sensibility is distributed all over the body, 
that the peristomial region near the gastrovascular orifice functions as a 
co-ordinating centre for movement, that the extremities of the tentacles 
are particularly sensitive, and that the cnidocil is a sensory element. 
He next describes his histological observations on Hydra , Laomedea , 
Podocoryne , Myriothela , and Tubularia, which have resulted in the 
discovery of facts which show that Hydra is not, as has been supposed, 
an isolated member of the animal series, but has a number of characters 
which are not only common to it and other polyps of the Hydromedusse, 
but also to the Anthozoa, and probably to all the Cnidaria. It may be 
shown to possess ganglionic cells and muscular cells with a refractive 
fibril ; the structure of its nematocysts is analogous to that of other 
polyps ; the cnidoblast is in relation with the nervous elements as in 
Lucernaria and the Actiniae ; and the peristomial region can be shown 
morphologically, as well as physiologically, to be the seat of the central 
nervous system. 
The author is, as may be supposed, led to reject the neuromuscular 
theory of Kleinenberg, though he cannot admit all the arguments which 
Korotneff advances against it. 
Formation of Blastostyle Buds in Epenthesis McCradyi.f — Mr. 
C. P. Sigerfors has investigated the mode of reproduction in this Medusa 
to which Dr. W. K. Brooks was the first to call attention. He finds 
that the reproductive organs may develope in one of two ways. They 
may form the normal organs with male or female cells, or they may give 
rise to blastostyles. In the latter case the young reproductive organ 
gets its ectoderm much thicker and many-layered, owing to the multipli- 
cation of its cells. Meantime the cells of the endoderm enlarge and 
become vacuolated, though still remaining a single layer. Before the 
organ becomes mature the outer layer of ectoderm cells is separated off 
from the rest by the appearance of a supporting lamella beneath it. 
When maturity is near, the endoderm pushes out evaginations into the 
* Bergens Mus. Aarsberet. for 1891 (1892) 24 pp. (1 pi). 
t Arch, de Biol., xii. (1892) pp. 647-82 (2 pis.). 
x John Hopkins Univ. Cire , xii. (1893) p. 106. 
