224 PROCEEDINGS OF THE ACADEMY OF [1887. 



Collected by Mr. B. W. Thomas from Calumet River, near Chi- 

 cago, Illinois ; also by Mr. J. G. Waller, "Ditchley's Manor," Es- 

 sex, England. 



Meyenia fluviatilis, var. gracilis, Carter. Ann. ami Mag. Sept. 1885, p. 180. 



"Sponge delicate in structure, Avhich is soft, whitish or colorless 

 in spirit, presenting the aspect of glue or sarcode when dry ; grow- 

 ing over the stem of an aquatic plant in a thin layer charged be- 

 neath with statoblasts (gemmules). Spicules of two forms, viz : 

 1, skeletal, very fine and delicate, acerate, curved, cylindrical, about 

 34 to 36 by 2-6000th. inch in its greatest dimensions ; chieiiy confined 

 to the fibi'e ; 2, statoblast spicules, shaft long, cylindrical, often slight- 

 ly curved, smooth, also very thin and delicate; head small, flat, radiate- 

 ly denticulated, the ends of the rays not recurved ; often umbonated 

 by a projecting spine or process; total length about ^ off oths.' inches ; 

 head 1 i-GOOOths. inches in diameter; shaft about five times longer than 

 the diameter of the head, about l-GOOOth. inch thick ; chiefly confined 

 to the statoblast, but also loose and numerous in the tissue generally. 

 Statol)last globular when wet, hemispherical and depressed in the 

 direction of the aperture when dry ; Avhen fully formed about 65 to 

 75-6000ths. inches iu diameter. Aperture slightly marginated, i. e. 

 slightly raised above the common level, about e Aoths. inches in diam- 

 eter. Surface of statoblast rough or uneven. In a section through 

 the centre the crust is seen to be a little thicker than the length of 

 the birotules, which, as usual, are arranged perpendicularly to 

 the yellow chitinous coat beneath and jDarallel to each other, \vith 

 one head resting on the chitinous coat and the surface of the other 

 free at the circumference ; cemented together and held in position 

 by the microcell-structure or "float," which, projecting above the 

 level of the outer heads of the birotules, gives rise to the roughened 

 state of tlie surface of the statoblast. Chitinous coat and germinal 

 contents the same as in the SpongUke generally. Size of specimen 

 sent to me about } by ^ inch horizontally." Carter. 



Loc. "Ice Factory Lakes, DeLand, Florida, near the St. John's 

 River." Collected by H. Mills. 



(6) Meyenia (Ephydatia) miilleri, Lieberkiihn. See Vejdovsky "Diagnosis." p. 177. 

 Of the varieties of this species v. amphizona and v. mirabilis as 

 well as those species which Mr. H. Mills has grouped under the gen- 

 eric name " Pleiomeijenia" as P. calumeticus, P. xvalkeri, and P. spin- 

 ifera, I can only say that they have been founded upon the presence 



