1887.] NANURAL SCIENCES OF PHILADELPHIA. 277 



mule birotulates ; d,d,d, single rotules ; c,e,e,e, exceeding- 

 ly misshapen forms. Collected by Dr. Geo. H. Horn. 

 Fig. VI. Meyenia subdivisa. From St. John's River, near Falatka, 

 Florida :-ffl, smooth, b, c, d, spined skeleton spicules; e,e, 

 e,e, long, massive gemmule birotulates, spined and sub- 

 spined ; .//, rotules of do. Collected by Henry Mills. 



Plate X. 



Fig. I. 3feyenia leldyi. From Schuylkill River, Philadelphia, 

 Pennsylvania :-a,a, a, smooth skeleton spicules, abruptly 

 pointed; h,b, do. with rounded terminations; c,c, short 

 birotulates with "entire" margins ; d, do. with rotule twist- 

 ed or exflected ; e, face of rotule ; /, group of rotules as 

 they appear upon the surface of the gemmules. 



Fig. II. Meyenia millsii. From Florida :-a, microspined skeleton 

 spicule ; b,b, mature gemmule birotulates with smooth 

 shafts ; c,c,g, probably immature forms ; d,d,d, face of ro- 

 tules, "lacinulate" or delicately notched, and without rays. 

 Collected by H. Mills; 



Fig. III. Meyenia everetU. From Pictou, Nova Scotia :-a, a, a, a, 

 smooth, slender skeleton spicules; b,b,b,b, long smooth, 

 gemmule birotulates ; e,c, d,d, minute dermal birotulates. 

 Collected by A. H. MacKay. 



Fig. IV. Meyenia everetti. From Gilder Pond, on Mt. Everett, 

 Massachusetts :-a,a,6,6, smooth skeleton spicules; c, c, c 

 gemmule birotulates ; d, end view of rotule formed of 

 hooked rays ; e,e,e, minute dermal birotulates. Collected 

 F. Wolle and H. S. Kitchell. 



Fig. V. Meyenia crater if ormis. From Crowe's Mill, Brandywine 

 Creek, Pennsylvania :-a,a, slender, microspined skeleton 

 spicules ; b,b,b,b, mature gemmule birotulates with short 

 hooked rays; c,d,e,e, supposed immature forms. 



Fig. VI. Meyenia plumosa, var. palmeri. From the Colorado of the 

 West, Mexico:-a, robust, microspined skeleton spicule; b,c,G 

 spined gemmule birotulates ; d,d, rotules of do., irregular- 

 ly notched ; e,e,e, sub-stellate dermal spicules ; /. imper- 

 fect form of do.; g,g, amorphous, "Scotch terrier" forms. 



Plate XL 



Fig. I. Heteromeyenia argxjrosjyerma. From Lehigh Gap, Penn- 

 sylvania •.-a,a, sparsely microspiued skeleton spicules ; 6, 



