1887.] NATURAL SCIENCES OF PHILADELPHIA. 177 



(4) Trochospongilla erenaceus, Ehrenbcrg. 



Syn:- 

 1846 Spongilla erenacexis, Ehreiiberg. 

 1856 " " Liel)erkuhn. 



1877 " " Vejdovsky. 



1881 Meyenio, " Carter. 



1883 Trochospongilla erenaceus, Vejdovsky. 

 1883 Spongilla " Retzer. 



1885 Trochospongilla " Wierzejski. 



Trochospongilla is of considerable dimensions, covering foreign 

 bodies in cusbion-like incrustations ; of a whitish or straw yellowish 

 color; skeleton spicules sharply pointed at both ends ; surface, except 

 at the extremities, covered with powerful spines. Parenchyma spic- 

 ules, correspondingly (?) small, smooth, and very often swollen in the 

 middle. Gemmulpe covered with spool-like amphidiscs whose rotules 

 have entire margins. They lie at the base of a deep air-chamber- 

 layer which consists of radially placed hollow columns, that are 

 divided into a number of chambers by cross-partitions. 



Trochospongilla erenaceus has been observed in many places in 

 Europe. In Germany by Ehrenburg; in Bohemia by Vejdovsky; in 

 Galicia by Wierzejski, and in Russia by W. Dybowski. 



(Ill) Gen. EPHYDATIA (Jray. Lamarck. 



Skeleton spicules either entirely smooth or entirely rough ; though 

 sometimes both forms are present together. In the air-chamber- 

 layers, around the gemmul?e, are embedded amphidiscs with star 

 shaped rotules, in one, two or three layers placed one over the other. 

 In the first instance they may be of equal length, but frequently 

 their lengths are unequal. 



(5) Ephydatia miilleri, Leiheiklilin. 



Syn: 



1816 Spongilla pulvinata, Lamai'ck. 

 1856 " mulleri, Lieberkiihn. 



1877 " " Vejdovsky. 



1878 TrachijspongiUa mdlleri, Dybowski. 



1882 Meyenia No. 2. 



1882 Ephydatia No. 2. 



1883 " mulleri, Vejdovsky. 



From A. Form B. var. astrodiscus, Vejdovsky. 

 1883 Ephydatia amphizona, part. 

 1883 Spongilla mirabilis, Retzer. 



1885 Mei/enia mulleri, Wierzejski. 



1886 EphydaUa " Fctr. 



