ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
51 
Tunicata. 
Heart Activity in Ascidia. — Edward C. Day ( Journ . Exper. 
Zool., 1921, 34, 45-65). There is a certain normal activity of the 
heart in Ascidia mentula, in which the number of beats is twenty-five 
for both ventral and dorsal series. The initial rate is 5*5 seconds per 
beat, and the pauses between the series average about 13 seconds. 
Stimulation, such as slicing pieces off the tunic, severing the nerves 
between ganglion and heart, and extirpating the ganglion, causes the 
number of beats to increase from twenty-five to fifty or ninety, the rate 
to drop from 5 * 5 to 5 or 4 * 5 seconds per beat, indicating acceleration, 
and the pauses to shorten from 13 to 10 or 8 seconds. In addition to 
these changes there is a retardation of the beat which manifests itself 
near the middle of a series. These changes go hand in hand with one 
another, and when any one of them is patently present, the others are 
present too. Exceptions occur in cases where the circulation has been 
interfered with through operation on the ganglion. The effects of 
stimulation abate and disappear in the course of an hour or a day, 
depending on the character of the operation, and the beat of the heart 
again exhibits its original normal characteristics. J. A. T. 
Reproductive Organs of Kukenthalia borealis. — Augusta 
Arnback Christie-Linde ( Proc . Zool. Soc., 1921, 187-96, 8 figs.). 
It is shown that testes and ovaries, supposed to be absent, occur in this 
compound Ascidian. The male organs, as well as the ovary and the 
ducts, are enclosed in a long, sac-like outgrowth of the mantle which 
extends into the common test. At the upper side of this sac there is 
sometimes another sac-like structure, evidently a brood-pouch. It may 
be a direct projection from the peribranchial cavity, or it may be formed 
in connexion with the oviduct. Apart from the gonads there are some- 
times isolated eggs in the mesoderm, and also in buds which grow out 
on both sides of the parent animal. J. A. T. 
Genus Atopogaster. — R. Hartmeyer (Zool. Anzeig ., 1921, 53, 
273-81). Among the Svnoicidse, with smooth or longitudinally-folded 
stomach wall, Herdman established the genus Atopogaster for forms with 
a transversely-folded wall. He doubted, however, if the five species of 
the genus formed a natural group. According to Hartmeyer, the 
transverse folding cannot be upheld and the five species are hetero- 
geneous. Two should be referred to Amour oucium fugiense, another is 
an Aplidium, and the two other are referable to the genus Polycitor. 
J. A. T. 
INVERTEBRATA. 
Mollusca. 
7. Gastropoda. 
New Pelagic Nudibranch. — Kristine Bonnevie (Zool. Anzeig ., 
1921, 53, 145-52, 5 figs.). In “Michael Sars ” material from the 
North Atlantic there occurred along with Glaucus and Phyllirhoe an 
altogether new type, Dactylopus michaelsarsii g. et sp. n., which seems 
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