292 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
They often contract to 50 p.c. or more, and the body-wall readily 
disintegrates, “ which soon reduces the creature to a most repulsive 
mass of slime.” Thus identification is not easy. The author deals with 
the systematic evaluation of size, colour, body-form, ambulacral append- 
ages, Polian vesicles, gonads, and calcareous particles. It appears that 
the calcareous particles are the only structures upon which much reliance 
can be placed in distinguishing species, but the body-form and the 
gonads afford characters of real value in distinguishing the genus, and 
the Polian vesicles may also furnish a generic character. About a score 
of species are dealt with, and the new genus Astichopus is established. 
J. A. T. 
Ccelentera. 
Classification of Actiniaria. — T. A. Stephenson {Quart. Journ . 
Micr. Sci, 1921, 65 , 493-576, 20 figs. ; 1922, 66 , 247-319). An 
important systematic revision. “ It is possible to guess at a small 
plankton swimmer with eight tentacles and eight mesenteries, without 
much definiteness of musculature, and with bilateral symmetry, and 
contrasting with, not resembling, the cruciform Scyphistoma, which 
must have been quite an independent outcome of a Hydrozoan. This 
small creature would give rise to several types much like itself but with 
differences of detail, each of which would give rise to a main Anthozoan 
sub-class. Only the one which gave origin to the Zoanthactiniaria 
need be followed here. This stock seemingly shed out curiosities at 
first ; some* of them took to burrowing and life in cracks, and became 
vermiform, but did not amount to much (Edwardsiaria) ; others went 
in for colonialism and incrustation, and had fair success in a coral-like 
way (Zoanthinaria). The main line, however, divided fairly early into 
two great groups, the split being upon the rock of sluggishness and 
colonialism and skeleton-building versus comparative activity, special- 
ization of the individual, greater muscularity, and no skeleton. The 
two groups are of course corals (Madreporaria) and sea-anemones 
(Actiniaria).” A few corals developed no skeleton, or lost it (Coralli- 
morphidae or Discosomidae). The sea-anemones proper gave off 
experimental forms (Protantheae and Ptychodacteae) ; the main line 
gave off two lesser lines (Athenaria and Endocoelactaria), and two great 
lines (Mesomyaria and Endomyaria). J. A. T. 
New Fresh- water Medusoid from Japan. — Asajiro Oka and 
Magoroku Haka {Annot. Zool. Japon ., 1922, 10 , 83-7). Description 
of Limnocodium iseanum sp. n. found swimming in an old well in the 
town of Tsu, Province Ise, Central Japan. It is near L. kawaii Oka, 
but differs in the structure of the velar statocysts (regularly spherical 
and confined to the base of the velum) and the manner of arrangement 
of the nematocysts on the tentacles. The largest specimens measure 
about 18 mm. across. It is highly probable that the unknown hydroid 
generation is hidden somewhere at the bottom of the well, which is 
about 2 * 5 metres in depth. The new species stands by itself, whereas 
L. kawaii and L. sowerlyi are more closely allied. J. A. T. 
