1892.] Zoology. 619 
there were many paler and many darker than any shown by Mr. 
Merrifield; and the larve and pupx had been kept under usual 
conditions, and the greater proportion of them followed the parent 
forms. In conclusion he said that such variation as was shown by 
Mr. Merrifield was impossible in nature except as a result of disease. 
Several gentlemen continued the discussion, Mr. Tutt following Mr. 
Fenn in attributing the variation to disease, and saying that to a large 
extent it was caused by preventing the proper development and forma- 
tion of the coloring pigment. He thought the action of temperature 
indirect, producing variation by interfering with the normal develop- 
ment. Mr. Merrifield agreed with many of Mr. Fenn’s observations 
and thought most of them consistent with his own experiments. In 
any case he thought that in the species studied by him the temperature 
was so moderate as not to interfere with health, and yet it produced, 
with great uniformity, considerable differences in color. In some 
other species no considerable changes were produced unless the tem- 
perature was so extreme as to produce crippling or imperfect develop- 
ment.—(Entom. Monthly Magazine.) 
A Curious Compound Ascidian.—In a current number of a 
Japanese zoological journal,’ Mr. A. Oka, now of Freiburg, i | Br., 
Germany, describes an interesting phenomenon in the life of a com- 
pound Ascidian, Diplosoma, which he collected some years ago at 
Misaki, Japan. As an examination of the accompanying diagram 
will show, the esophagus of each indi- 
vidual Ascidian is divided into two 
branches (o and 0”), each branch ter- 
minating in one branchial basket (b’ 
and b”) respectively. The branchial 
basket indicated by the dotted line (b”) 
is old, while the other basket (b’) is 
young and functional. On the other 
side of the cwesophagus is represented a 
young bud (0) which, when fully un- 
folded, becomes a functional branchial 
apparatus, and takes the place of (b’); the oldest basket (b”) having 
disappeared by that time. Various intermediate stages indicating this 
state of transition have been observed. In such forms the esophageal 
end of the alimentary canal shows division into three branches. The 
! The Zoological Magazine (Japanese), vol. iv, no. 42, pp. 144-146, April 15, 1892. 
Tokio, Japan. 
