60S 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
There does not seem to be much room for doubt that the mesenteries 
of the Rugosa increased in a bilateral manner, but it is still a matter for 
doubt whether the primary plan of the organism was hexamerous or 
tetramerous. In any case, the mode of formation of the septa in the 
Rugosa seems to have been entirely different from that which obtains in 
the Hexacoralla, and it is, therefore, unlikely that there is any intimate 
relation between the two groups. 
The Alcyonaria were, possibly, antecedent phylogenetically to the 
Edicardsise ; the arrangement of the mesenterial musculature seems to the 
author to be simpler, and the slight development of the siphonoglyphs a 
point of considerable importance. At any rate, the group is one that is 
very highly specialized. A pressing need is the careful and comprehen- 
sive study of the filaments of the Alcyonaria. Provisionally they are 
regarded as forms which branched off from an Octactinian ancestor which 
they had in common with the Edwardsiae. 
It is still difficult to suggest the history of the Antipatharia, but 
Prof. M‘Murrich is inclined to regard the six-mesenteried condition as 
the more primitive. 
The phylogenetic diagram given in the preceding page is offered. 
The term Protactiniae denotes an order consisting of forms with 
twelve primary mesenteries ; and with one or a pair or two pairs of 
secondary mesenteries on each side of the sagittal axis; this order 
includes Scytophorus , Gonactinia, and Oractis. 
Coral-Studies.* — Dr. A. R. v. Heider discusses under the above title 
a coral which Heller described as Madracis pharensis , Astrocoenia 
pharensis n. sp. It belongs to the family Oculinidae and to the genus 
Madracis , to which should also be referred Axohelia M. Edw. et H., 
Astrsea decactisJjjman, StylopJiora incrustans Duch.et Mich., and JReussia 
lamellosa Duch. et Mich. The genus Madracis includes two species — 
M. decactis Yerrill from the Atlantic and M. pharensis Heller from the 
Adriatic, which differ in the marking and colouring of the polypes. 
Medusae of Millepora Murrayi and Gonophores of Allopora and 
Distichopora.t — Dr. S. J. Hickson finds that the male gonads of 
M. Murrayi are borne by medusae which escape from the ampullae in 
which they are developed before the spermatozoa are matured ; the ova, 
as in M. plicata, are extremely small and alecithal. They move in an 
amoeboid manner in the coenosarcal canals, and do not ultimately rest in 
gonophores or in any specialized portion of the system. The medusae 
have no radial or ring canals in the endoderm of the umbrella, no velum, 
no sensory organs, and no mouth ; they are formed by the metamor- 
phosis of either a dactylozooid or a gastrozooid. The sperm-cells 
originate in the ectoderm of the coenosarc and wander into the ectoderm 
of the zooids, where they fuse into aggregations to form a spermarium. 
This last causes in time a retrograde metamorphosis of the tissues of the 
dactylozooid, at the distal extremity of which it is formed. A cup- 
shaped outgrowth next appears which' forms the umbrella of the medusa, 
and subsequently a conical growth of the endoderm penetrates into the 
substance of the spermarium and forms the manubrium. 
* Zeitschr. f. Wise. Zooh, li. (1891) pp. 677-84 (1 pi.), 
t Quart. Journ. Micr. Sci., xxxii. ^1891) pp. 375-407 (2 pis.). 
