ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
299 
Another feature is the enormous size, as seen in Hebella contorta and 
H. scandens. Many forms are symbiotic ; thus, on Acanthella effusa 
there sits a Sertulariau, and on both Hebella contorta grows. 
Ampullae in Millepora.* * * § — Prof. S. J. Hickson has found these cavities 
(in which he discovered a male medusiform gonophore in 1890), not 
only in Millepora Murrayi , but in other museum specimens, labelled 
M. Schrammi , M. alcicornis , M. complanata. 
Porifera. 
Lithonina.t — Prof. L. Doderlein describes Petrostroma Schulzei, re- 
presenting a new group of Calcareous Sponges (Lithonina). The new 
form is Millepore-like or Polyzoon-like, and was found in deep water 
(200-400 m.) off the Japanese island of Enoshima. Only dry specimens 
were studied. The cortical layer consists of numerous free tetracts and 
triacts, besides dense bundles of peculiar forked spicules. In the deeper 
portions a connected framework has been formed by the fusion of tetracts 
with plump arms. It presents marked resemblances to the fossil Phare- 
trones, which are the only known calcareous sponges with a coherent 
skeleton. With these Dendyhas also associated Lelapia australis Carter, 
in which forked spicules are united in rigid strands. But Doderlein 
points out that, in spite of the likeness of Petrostroma to certain Phare- 
trones, there is this great difference, that in the latter the spicules are 
united in bundles by some cementing substance, while in this new form 
a real fusion of spicules has occurred. 
Protozoa. 
Physiology of the Cell.J — Dr. M. Verworn has continued his inter- 
esting observations and experiments on Protozoa. He has studied the 
phenomena of contractility and irritability in Eed Sea Phizopods — 
Orbitolites complanatus , Amphistegina Lessonii, Hijalopus ( Gromia ), Du- 
jardinii , and a new form, Phizoplasma Kaiseri. Among his conclusions 
we note the following : — (a) The transport of plasmic material in the 
cell is quite distinct irom the propagation of a stimulus ; (6) removal of 
oxygen acts first on the expansion of pseudopodia, secondly on their 
retraction, and ends in inducing paralysis of both ; (c) the change from 
positive to negative thermotropism after a certain temperature is exceeded 
is due to the fact that the expansion and retraction phases have different 
limits. At 30°-32° C. for Phizoplasma the expansion and retraction 
phase are equally stimulated ; below this optimum of movement the ex- 
pansion phase is most strongly stimulated, above the same optimum the 
contraction phase is most stimulated. 
New Flagellata.§ — Herr Hs. Meyer describes the following new 
species: — Mastigamceba commutans, Dimorpha digitalis , D. bodo, Monas 
minima , M. amoebina , 31. sociabilis , Ochromonas tenera, O. granulosa, 
O. variabilis, and O. chromata. He also gives useful diagnoses of the 
* Mem. and Proc. Manchester Lit. Phil. Soc., xli. part 2 (1897) Mem. 5, pp. 1-4. 
t Zool. Jahrb. (Abth. Syst.), x. (1897) pp. 15-32 (5 pis.). 
t SB. Akad. Wiss. Berlin, 1896, pp. 1243-54. 
§ Rev. Suisse Zool., v. (1897) pp. 43-89 (2 pis.). 
