690 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Springer on Palaeozoic Echinoderms, lias prepared a report on tlie 
Mesozoic forms ; he is convinced that further study will show that many 
of the North and South American forms will be found to he identical, 
but the identity of American with European species seems doubtful. 
Ccelentera. 
Revision of Alcyonaria Stolonifera.* — Prof. S. J. Hickson, in 
offering a revision of the genera of this group of Alcyonarians, prefaces 
it with some remarks on the reception (or rather want of it) given to his 
proposal, made in 1883, that those Alcyonaria in which the polypes 
spring independently from a basal stolon should be separated as a 
special sub-order, the Stolonifera. The order Alcyonaria is divisible 
into the Protoalcyonaria or solitary forms, Stolonifera, Alcyonacea, 
Gorgonacea, and Pennatulacea. The Stolonifera are Colonial forms, 
with a membranous or ribbon-like stolon ; mesogloea poorly developed ; 
polyps either entirely free from one another except at their bases, 
or connected by horizontal platforms ( Tubipora ) or connecting tubes 
(' Clavularia ). The skeleton is composed of calcareous spicules, which 
may be joined together, free or absent. The group contains the Tubi- 
poridfe and the Clavulariidse, the latter being represented by Clavularia , 
Cornularia, Stereosoma g. n. and Sympodium , with possibly the fossil 
Syringopora ; this family Clavulariidse is practically the same as the 
Cornulariidae of other authors, and reasons are given for proposing the 
change of name. 
In the family Cornulariidse the authors of the ‘ Challenger ’ Report 
on the Alcyonaria included sixteen genera, and some severe remarks are 
offered on the way in which their work was done. 
The new genus Stereosoma is established for S. celebense sp. n., 
which is remarkable for the absence of contractility, and the separation 
of the tentacles from one another by very considerable intervals. The 
want of contractility is not due to the presence of spicules, for there are 
none, but to a tough, vacuolated, homogeneous substance lying above the 
mesogloea. Clavularia garcise , C. reptans, and C. celebensis are new 
species, of which, as of some already described forms, accounts are 
given. The coloured plates illustrating this memoir are of peculiar 
beauty. 
Heliopora cserulea.j — Mr. G. C. Bourne publishes an abstract of a 
memoir on the structure and affinities of H. cserulea , with,- some observa- 
tions on Xenia and Heteroxenia. It is found that the cuticles and 
coenenchymal tubes of Heliopora have not each their distinct and proper 
■wall, but that the walls are common to them and to adjacent tubes ; this 
genus and its allies may therefore be distinguished as the Coenothecalia 
from forms like Tubipora, which are Autothecalia, or have each corallite 
separate and distinct. 
Heliopora is not the only Alcyonarian that has a distinct ectodermic 
skeleton, for Xenia and Heteroxenia have a spicular ectodermic skeleton. 
In the Xeniidse, as in the Helioporidae, most of the coenenchymal meso- 
gloea and the whole of the calcigenous elements are derived from the 
