103 
1887 Ephydatia mülleri Vejdovsky in Potts Monograph Fresh- 
water Sponges. Proc Acad. Nat Sei Philadelphia 
p 177. 
1887. Ephydatia mülleri Wierzejski. Zool. Anz. Jahrg. 10 pp. 
122—126. 
1895 Ephydatia mülleri Weltner. Archiv f, Naturg. 1895, Bd. 
I. p 125. 
1903. Ephydatia mülleri Zykoff. Bull. Soc. Nat. Moscou 1903 
p. 42. 
1903 Ephydatia mülleri Skorikow. Jahrb. Biol. Wolga-Station 
Hft. 1. p. 33. 
Lieberkühn's original description of the species was based 
on specimens found in the Spree at Berlin. He States that the 
surface of the skeleton spicules was finely spined (höckerig) 
and that the margins of the disks of the amphidisks were 
jagged. 
The next important reference was that of Dybowski who, 
in 1882, described various Russian forms of this species under 
the designations M e у e n i а Л! 2 and Meyenia JNI? 3 vars 
а and ß, the forms and varieties being chiefly distinguished by di- 
fferences in the size of the amphidisks, in the degree and 
kind of incision in the disks of these spicules, and in the size 
and surface-characters of the skeleton spicules. 
ln 1883 (i) Vejdovsky gave а detailed account of these 
varieties which he names Forma A, Forma В and var. 
astrodiscus. Fle regarded Form А as identical with 
Meyenia № 2, Form В as similar to M e у e n i а № 3 
var а (from Niankow), and var astrodiscus as being the 
same as Meyenia № 3 var ß (from Chalaktir See) 
In 1883 ( 2 ) he described а new species E. amphizona 
with а double layer of amphidisks round the gemmules, and 
rekorded E. mülleri var. astrodiscus asa synonym of 
E. mülleri (typica). 
In Pott’s Monograph (1887) he included all the above 
forms and varieties, and also the species E amphizona 
under E. mülleri. 
In 1887 Wierzejski described the blasenzellen present in 
E. m ü 11 e r i. 
Weltner (Naturw. Wochenschrift 1892 p. 4І6) writes 
„lmWeichkörper, besonders in der äusseren Haut finden sich 
sehr grosse blasenförmige Zellen, bestehend aus einem dün- 
