424 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
tribute the genera referred to it among the other two families. The 
author takes occasion to distinguish by definite names those various 
forms of dermal ossicles which are generally called paxillae. These he 
calls spinopaxillm, parapaxillae, protopaxillae, and pseudopaxillae. 
A new genus named Acanthar chaster is made for a remarkable form 
apparently closely allied to Pontaster. The type of this genus was 
originally described as Archaster dawsoni. In dealing with the Ophiurans 
new species only are described. 
Ccelentera. 
British Museum Catalogue of Stony Corals.* — Mr. H. M. Bernard has 
prepared a second volume of the Catalogue of the Stony Corals in the 
British Museum, in which he deals with the genera Turhinaria and 
Astrseopora. We have from time to time called attention to his pre- 
liminary notes on these forms. 
Perhaps the most interesting point in his introduction is that in 
which he deals with the question, Is any classification of the various 
forms composing a genus into separate clearly defined species possible ? 
Answering this question so far as it concerns his own work, he says 
that “ the only specimens which can be claimed with absolute certainty 
as specifically identical, are a few which have in each case been gathered 
at the same place and time, and resemble one another as closely as if they 
were two fragments of one and the same stock. Beyond these no cer- 
tainty exists, and strict regard to the variations of form and structure 
would compel us to label all the remaining specimens as different species 
or varieties. Further, I do not remember ever having seen a specimen 
in either private or public collections which exactly recalled any single 
specimen in the British Museum. Are all these to be classed as new 
species ? Such a course is only possible when the collection dealt with 
is very small, but when the number of specimens is measured by hun- 
dreds, one’s courage fails. Hence recourse is had to a recognised but 
hardly satisfactory system of grouping ; certain striking and conspicuous 
specimens, or single specimens which have already been described by 
previous workers, are selected as types, and the remainder are divided 
according as, in the opinion of the individual worker, they approach 
one or the other of these favoured specimens. The types are thus in 
the highest degree arbitrary and accidental, as is also, it must be con- 
fessed (though in a less degree), the selection of other specimens to 
be associated with them.” 
In the present volume 260 specimens of Turhinaria are grouped round 
some fifty such types. Mr. Bernard thinks that we are rapidly nearing 
the time when our ever-increasing collections, revealing as they do the 
infinite grades of variation presented by living organisms, will compel 
us to break loose from the restraint of the Linnean species. It will be 
remembered that the first volume of this catalogue, prepared by the late 
Mr. Brook, dealt with the genus Madrejpora. The present author finds 
that it, with Turhinaria and Astrseopora, forms a well-demarcated group 
of ccenenchymatous corals, that is, of corals out of the development of 
* ‘ Catalogue of the Madreporarian Corals in the British Museum,’ vol. ii. London, 
1896, 106 pp. and 31 pis. 
