Kingsley.] 
450 
[March 15, 
development. My comments on these statements are simply a 
flat denial. The eggs of Molgnla hatch directly into tadpoles, 
which differ greatly from those described by Dr. Tellkampf, and 
then by a regular process of growth produce the Ascidian. So 
far as my observations go there is not the slightest thing to war- 
rant Dr. Tellkampf s assertions and conclusions or to connect the 
Mammaria (which by the way I have never seen) with Molgula. 
It is, however, but just to say that Dr. Tellkampf does not say 
that he has witnessed the whole process which he describes but 
that he in one or two important points allows inferences to take 
the place of observation, and it is in exactly these places that his 
errors may have crept in. It now remains for some one to inves- 
tigate these Mammariae and their larvae and ascertain exactly 
what they are. 
Note. — I would here return mv sincere thanks to Prof. Alpheus Hyatt, Mr. 
B. H. Van Vleck, and Dr. C. S. Minot for the facilities I enjoyed while pursuing my 
studies in the summer laboratory of the Boston Society of Natural History, at Annis- 
quam, during the summer of 1881 . 
EXPLANATION OF PLATE IX. 
[The same letters are used in all figures.] 
a. 
atrium. 
l.p. 
lateral processes. 
a.a. 
atrial aperture. 
n. 
nucleus. 
a.n. 
arms. 
n'. 
nucleolus. 
b. 
blastopore. 
n.c. 
notochord. 
b.o. 
branchial opening. 
0. 
oesophagus, 
b.r. 
branchial rings. 
o.b. 
“organ of Bojanus.” 
e. 
eye. 
P- 
process. 
en. 
endostyle. 
s. 
stomach. 
ep. 
epiblast. 
s.c. 
spinal cord. 
f.p. 
frontal process. 
t.c. 
“ testa cells.” 
h. 
heart. 
t. 
tail. 
by. 
i. 
hypoblast. 
intestine. 
t.f. 
tail fold. 
Fig. 
. 1. Very young 
ovarian egg. 
Fig 
2. Ovarian egg 
OO 
with nucleus and 
nucleolus, the “ testa cells ” not 
yet developed. 
Fig. 
3. Ripe egg surrounded by “ testa cells.” 
Fig. 
4. Egg at the 
OO 
close of the first 
segmentation, the blastomeres 
mostly composed of deutoplasm, the little protoplasm being gathered 
around the upper poles of the segments. 
