220 Proceedings of the Royal Physical Society. 
The only previous indication of the presence of the polar caps, which must 
be of some importance in the formation of the spindle te is to be 
found in two figures of Borgert (1). 
LIST OF REFERENCES. 
1: Borgert. Arch. f.. Prot. xx. VOn0: 
2. Forp, Arch. f. Prot., xxxivaetoiee : 
3. JOLLOS. Arch. 7. Prot.,-xix., 1910! . 
4. Keyssevitz. Arch. f. Prot., xi., 1908. 
5, LAUTERBORN. Zeitschr. f. wiss. Zool,, lix., 1895, 
6. SENN. Zertschr. f. wiss. Zool., xevii., 1911, 
XVITI.—Rhabdameeba marina, gen.n.etsp.n. By J.S. Dunkerly, B.Sc., 
Lecturer in Zoology, University of Glasgow. 
(With Teat-figures.) 
(Received 26th October 1920. Read 22nd November 1920.) 
THE organism described in this note was found in some cultures of Oxyrrhis 
marina (division stages of which are described above). The culture 
medium was Allen and Nelson’s modification of Miquel’s solution in sea 
water, and the cultures had been started with some 77richospherium material q 
from the Marine Laboratory, Plymouth. Coverslips were floated on the 
surface of these cultures for twenty-four hours, then fixed in Bouin’s fluid 
and stained with iron hematoxylin by Dobell’s method. 
It was not until the mounted preparations were examined that the organ- 
ism which is the subject of this note was discovered. The preparations had 
been made some months before being examined and the organism has not 
been seen again in the cultures, but, unfortunately, circumstances prevent 
at present a prolonged search of the cultures. It may be useful, therefore, 
to describe the appearance of this peculiar creature in the preparations, as 
it is so distinctive, and no published figures or description seem to fit it. 
Rhabdameba marina, gen. n. et sp. n., is a minute amceboid organism, the 
longest diameter being 10, and the diameter of an average rounded r 
specimen (Fig. 1) only 75». The protoplasm is extremely thin and — 
transparent, the organism being visible only under the best lighting 
conditions. There is a central vesicular nucleus with a small karyosome 
and faint extra-karyosomatic granules (chromatin ?) (Figs. 1-3). In some 
