ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 63 
good diagnosis is given. Then follows an appalling list of forty-six 
species referred to Plexaura erroneously, and another of thirty-seven 
which should be included in the genus but have been otherwise named. 
Nineteen secure species are recognized, and a diagnostic key is given. 
Then follow descriptions of four new species. J. A. T. 
Scyphomedusan Jelly-fishes from the Philippines. — S. F. Light 
(. Philippine Journ. Sci., 1921, 18, 25-46, 4 figs.). Thirty-nine species 
and varieties of Scyphomedusae are known from Philippine waters— a 
surprisingly large number. The present paper describes two new genera 
and one new species. One of the new genera is Anomalorhiza, a dicho- 
tomous Rhizostome, differing'strikingly from other genera in the unusual 
branching of the mouth arms, which are dichotomously branched only 
near the tip, the entire outer surface of the arm being quite bare ; in 
the presence of a very large, distinct ring canal ; in that the interocular 
canals are but eight in number ; and in the absence of any externally 
visible musculature. The other new genus is Cotylorhizoides , also a 
dichotomous Rhizostome, with eight simple bifurcated mouth arms, the 
terminal branches pinnate. There are no radial muscles. The strong 
circular muscles are interrupted in the eight principal radii. The 
circular canal is small or absent. The bell is high and dome-shaped, 
without a central dome-shaped region as in Gotylorhiza. The two new 
genera emphasize, what Mayer has pointed out, that the group Rhizo- 
stomata dichotoma is not sharply defined from Rhizostomata triptera. 
J. A. T. 
Classification of Actiniaria. — T. A. Stephenson {Quart. Journ. 
Micr. Sci ., 1920, 64, 425-574, 1 pi., 32 figs.). In this very important 
revision of the sea -anemones the author seeks to show that the exact 
form of the pedal disc, the presence or absence of capitular ridges, the 
thickness of the body-wall, and the form of the tentacles apart from 
actual structural differentiation of parts of them, are characters which 
it would be profitable to discard as sole generic distinctions ; that the 
distribution of the gonads is not invariably a reliable generic character ; 
and that presence or absence of definite verrucas and acrorhagi, and of 
a cuticle in some cases, the presence or absence of basal swellings or 
other tentacular specializations, the limitation of the cycles of tentacles 
to two only (at the same time as the mesenteries are normally arranged 
in several cycles) in some forms, the form of the retractor muscles in 
most cases, the position of the longitudinal tentacular musculature 
(whether ectodermal or mesogloeal), and the presence or absence of 
the mesogloeal sphincter, are more valuable characters which may usually 
be emphasized in distinguishing genera. J. A. T. 
Symbiosis of Siphonophora and Zooxanthellae. — M. Kuskop {Zool. 
Anzeig ., 1921, 52, 257-66, 7 figs.). A discussion of the symbiotic 
Zooxanthellae in Velella spirans and Porpita umbella. In Velella they 
occur especially in the so-called hepatic canals, the sail, the endoderm 
cells of the margin, and in the medusoids. The larvae are infected very 
early, probably through the mouth. In Porpita the symbions are very 
abundant in the hepatic canals. In both types they may crowd out into 
the mesenchyme. There is, however, a general suggestion of a 
regulated partnership, not of a random infection. J. A. T. 
