ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
45 
show that the Drs. P. and F. Sarasin were incorrect in regarding the 
great development of the organs of Stewart as a characteristic of the 
Echinothiiriidfe,* for in Phormosoma these organs may be altogether 
absent, or small vestiges may be present in some only of the rays. 
The muscles, which were described as dividing the test into a number 
of compartments, and as causing the vermicular motions of Aethenosoma 
urens, are also absent from Phormosoma, and are poorly developed in 
A. pcllucidum. Astrogonium greeni is a new species, as is Holothuria 
aspera, and both, like Phormosoma, come from 1000 fathoms. Anfedon 
hifida was found 150 fathoms lower than the 100 fathoms, already 
recorded as its greatest depth. Nijmphaster protentus, by Sladen 
among the Starfishes of the ‘ Challenger,’ is an addition to the British 
deep-water fauna. Echinus microstoma, which was incompletely described 
by Wyville Thomson, is refigured, and measurements of it are given ; 
some of the characters of E. elegans are discussed. An account is given 
of the variations presented by a number of specimens of Spatangus 
rasclii, and it is pointed out that in discussing the question of the utility 
of specific characters we must exercise the greatest caution in the selection 
of the points of structure which we use as such marks. To such a 
question, and to the allied one, how far are characters that vary wdthin 
considerable limits to be so used as specific, the answers that may be 
given must be tentative, and not dogmatic. 
Comatulse of Mergui Archipelago-t — Dr. P. H. Carpenter describes 
the six species of Comatulae collected by Dr. John Anderson in the 
Mergui Archipelago. Five belong to the genus Antedon, and of these 
A. Andersoni is alone new ; it belongs to what Dr. Carpenter has called 
the elegans-group but differs from known representatives in being bidis- 
tichate and not tridistichate, and in not having a well-plated disc. It 
is remarkable for the rarity of the syzygies in the arms ; w^ere the 
species fossil and the lowest portions of the arms alone preserved, and 
that badly, it would be possible to miss these unions altogether. The 
author suspects, therefore, that Walther’s attempt to establish the 
absence of syzygies as a diagnostic character of Solanocrinus is partly 
due to a generalization in imperfect material. Actinometra notata sp. n. 
is described as a fine species allied to A. paucicirra, but differing from 
it in always having palmars, and sometimes twice as many arms. There 
is a very remarkable, and at present inexplicable, distribution of the 
grooves, for though all the arms are grooved, the ambulacrum from the 
left posterior angle of the peristome comes to a sudden ending on the 
disc, immediately after its first bifurcation ; all the ambulacral grooves 
of the corresponding ray are connected with the single groove-trunk 
which comes round the right side of the disc. This abnormal arrange- 
ment does not seem to be accidental, but it may be due to parasitic 
growths. 
Echinoidea of Mergui Archipelago.J — Prof. P. M. Duncan and Mr. 
W. Percy Sladen report on the six species of Echinoids collected by Dr. 
John Anderson. All are known ; and the most remarkable points are 
that all the regular forms belong to the family Termopleuridae, and there 
* See this .Journal, 1888, p. 956. 
t Journ. Tunn. Soe., xxi. (1889) pp. 801-16 (2 pis.). + T. e., pp. 816-9. 
