486 ZOOLOGY. 
sponges generally the large oscules from which flow the currents 
of effete water are uppermost. The ends of the threads of the 
fascicle, with their reversed hooklets, are also well adapted to 
adhere to objects.” Prof. Leidy, then noticing that the ‘ beautiful 
Euplectella of the Philippines was also at first represented upside 
own,” concludes by giving a clear description of the Pheronema, 
a sponge ‘‘apparently intermediate in character with Hyalonema 
and Euplectella—(which would) “appear to throw some light 
upon the question of what belongs to Hyalonema.” 
The observation of Prof. Thomson, to which I have referred, will 
be found on page 426, and is as follows: “ Perhaps the most sin- 
gular circumstance connected with this discussion was that all this 
time we had been looking at the sponge upside down, and that it 
had never occurred to any one to reverse it.” Reading this quota- 
tion by itself one would naturally suppose that Prof. Thomson 
had simply been ignorant of what Dr. Leidy had already eit 
but at page 418 of the same work, “the Depths of the Sea,” i 
describing a sponge resembling Holtenia, Prof. Thomson aop 
‘I was inclined at first to place this species in the genus Phe- 
ronema, but Dr. Leidy’s description and figure,” ete. Evidently, 
then, Prof. Thomson was familiar with what Dr. Leidy had pub- 
lished in reference to these sponges. Why therefore does he 
unjustly ignore the fact that Dr. Leidy was the first to describe 
correctly the position of Hyalonema by saying “ we had been 
looking at the sponge upside down and that it had never occurred 
to any one to reverse it.” We trust that Prof. Thomson will now 
gracefully throw up the sponge. — Henry C. CHAPMAN. 
EMBRYOLOGY OF THE LEPIDOPTERA.—The distinguished Russian 
embryologist, Prof. A. Kowaleusky, gives us in a late memoir 
(Embryological studies on Worms and Anthropods, St. Peters- 
burg, 1871), the first definite information we possess as to the 
mode of development of the Lepidoptera. He finds that develop- 
ment goes on very uniformly in very remote genera. The primi- 
tiye band is confined to one side of the eg gg and sinks a little way 
into the yolk ; it is thusan endoblast, as Dr. Dohm had previously 
stated from the observations of Herold. The outer membrane, 
which surrounds the yolk, and is developed from the primitive 
blastoderm (the amnion of most authors), is called the “serous 
brane,” by Kowaleusky, while the inner membrane, which 
