1886. ] Embryology. 823 
heart of echinoderms. His study of Asterias hyadesi, a new 
star-fish from Cape Horn, has led him to conclusions identical 
with those arrived at from the study of Comatula. The “heart” in 
Comatula is but a glandular organ, the point of departure of the 
reproductive organs, and there are no true vessels, only irrigation 
canals in which sea-water always runs. Part of the water whic 
enters by the madreporic plate of Asterias passes into the sub- 
ambulacral cavities, the schizocele, and the genital cavity., Sea- 
water plays the part of blood not only in echinoderms, but in all 
zoophytes, which M. Perrier believes ought to form a sub. king 
le 
dom, as arranged by De Blainville. 
Vol. 1x, No. I, 1885. M. Stossich (Boll. d. Soc. Adri. d. Sci. 
Nat. 1885) gives an account of various species of Distomum and 
allied genera found in the intestines of fishes in the neighborhood 
of Trieste. 
EMBRYOLOGY." 
, Tae Devetopment oF THE Mup-mMrnNow.—The ova of Umbra 
limi measure 1.6™™ in diameter and are laid singly upon aquatic 
Plants to which they adhere for a time by means of a thin coating 
of adhesive matter which invests them. The vitellus and blasto- 
disk is moderately clear and yellowish in color. Just underneath 
the blastodisk there is a rounded, flattened cluster of highly re- 
fringent oil-drops of small size. As the blastodisk spreads these 
oil-drops become more and more diffused or scattered over the 
vitellus just beneath the blastoderm. : 
At the time of the formation of the blastodisk, the vitellus: dis- 
Plays a most active amceboid activity of its substance. TI 
active that the outline of the vitellus changes very distinctly at 
of a few seconds. In fact, I know of no teleostean egg 
Which has been hitherto described in which such amceboid move- 
ments of the vitellus are so pronounced and rapid. 
! Edited by Jonny A. RYDER, Smithsonian Institution, Washington, D, C, 
