STUDIES ON FRESH-WATER BRYOZOA. XVI. FREDERICELLA AUSTRALIENSIS VAR. BROWNI, N. VAR

¹ Marine Biological Laboratory and College of New Rochelle

1. The species Fredericella australiensis has been emended to include three varieties.

2. A new variety, F. australiensis var. browni, has been erected.

3. Two other previously recorded forms, F. australiensis Goddard 1909 and F. sultana subsp. transcaucasica Abricossoff 1927 have been reduced to the status of varieties under the emended F. australiensis.

4. The emended F. australiensis is characterized by its roundéd or broadly elliptical sessoblasts, its wider zooecial tubes, its greater tentacle number, its lack of dissepiments and the shorter stubbier tentacles and polypides which are generally confined to the tips of the tubes. These features distinguish it from F. sultana.

5. The varieties australiensis, browni, and transcaucasica are placed in F. australiensis because they possess the above characteristics.

6. The three varieties are distinguished from each other on the basis of degree of incrustation of their ectocyst, the difference in number of tentacles, appearance of the zooecial tubes in cross section and miscellaneous measurements.

7. Fredericella australiensis has a wide but scattered distribution. It is represented in Australia by var. australiensis; in Eurasia (the U.S.S.R.), by var transcaucasica, in Africa?; and in North America, by var. browni.

8. The specimens which were immediately responsible for the erection of the new variety, F. australiensis var. browni, were obtained through the kindness of Dr. C. J. D. Brown and Dr. H. van der Schalie of Ann Arbor, Michigan, who turned the collection over to the author for study. The specimens were collected by Dr. van der Schalie on August 3, 1942, from rocks in an alkali pond about three miles northeast of Church Butte, Uinta County, Wyoming, U.S.A.

9. The study includes 14 illustrations and one table of measurements dealing with var. browni and one table of comparison between the three varieties.

10. A brief summary of available measurements and other data on F. sultana is given.