162 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
elaboration of the vascular system. In the author’s opinion the evidence 
in support of this theory is overwhelming. A collective name, Branchio- 
trema, is suggested to include all animals with gill-slits, whether in the 
adult or in the embryo. 
Rotatoria. 
Rotatoria of the Basin of the Lake of Geneva.* — In the December 
number of this Journal of last year (p. 630) Dr. E. F. Weber’s first part 
of this elaborate paper was noticed, and now the second part, dealing 
with the Ploima and Scirtopoda, has appeared. The author gives very 
good original figures, full of anatomical details, of the 88 species so far 
found by him in this district, and the text can be commended for its lucidity 
and exactness. In the whole paper, dealing with 123 species, only one 
is described as new ; this is a lesson to the inexperienced students who 
so frequently describe new species of Rotifers by the dozen and by the 
score from a single small lake. Of slight changes introduced in the 
names, may be noticed that of Furcularia lacinulata , now called Diaschiza 
lacinulata, to which genus this species undoubtedly belongs. The genus 
Sacculus (Gosse) is changed into that of Ascomorpha (Perty) which has 
the priority in point of date. Three new families : Ploesomad2e, Gas- 
tropodid2e, and Anapodid.®, are created for the reception of the recent 
and aberrant genera Ploesoma , Gastropus, and Anapus respectively. 
List of Rotifera found in the Illinois River at Havana, Ill.f — Mr. 
Adolph Hempel publishes this list with notes as to locality, frequency, 
seasonal distribution, &c., which gives a good idea of the work done at 
one of the various fresh-water biological stations, which have of late years 
been started by several Universities and State laboratories in America. 
100 species are enumerated, but none that has not already been described. 
Trochosphaera solstitialis.J — During the past summer Mr. H. S. 
Jennings has found this very interesting and rare rotifer at another 
American station, a swamp adjoining Lake Erie, which is widely sepa- 
rated from the first station on the Illinois river, where Dr. Kofoid found 
it. A well-mounted specimen has reached this country, and has been 
exhibited at the March meeting of the R.M.S. 
Echinoderma. 
Development of Ophiura olivacea.§ — Mr. C. Grave gives a pre- 
liminary account of the development of this Ophiuroid. For Echino- 
derms, the eggs of Opliiura olivacea Lyman are very large, with much 
yolk. They are quite opaque, and vary in colour from green to orange- 
yellow, but the eggs of one individual aro constant in their coloration. 
Soon after fertilisation two membranes are formed. When 36 hours 
old, the larvse are oval in form, and swim actively by cilia which cover 
the entire surface. The blastopore is shifted from the posterior end to 
a ventral position by the unequal growth of the ventral and dorsal sides. 
From the blastopore there protrudes the end of a cellular mass of 
material which almost fills the cavity of the archenteron, and also 
* Rev. Suisse de Zool., v. (1898) pp. 355-785 (10 pis.). 
t Bull. Illinois State Lab., v. (1898) pp. 301-88. 
j Science, 1898, p. 551. § Zool. Anzeig., xxii. (1899) pp. 92-6 (5 figs.). 
