1887.] NATURAL SCIENCES OF PHILADELPHIA. 279 



ulates more neai'ly equal than in either of the former cases, 

 as shown again hj-fj,g,g, end views. 



Fig. IV. Carterius tenospervia. From Lansdowne Run, Philadel- 

 phia, Pennsylvania .-a,a, skeleton spicules ; b,b,b,c, spined 

 gemmule birotulates with burr-like rotules ; e,e,e, ends of 

 do.; d,d,d,d, long, spinous, acerate dermal spicules. 



Fig. V. Carterius latitenta. From Chester Creek, Pennsylvania:- 

 a,a, skeleton spicules ; b,b,b,b, gemmule birotulates, varia- 

 ble in length ; d,d, face of rotules ; c, spined dermals. 



Fig. VI. Carterius tubisperma. From Niagara River, near Buffalo, 

 New York :-a,a, skeleton spicules ; b,b,b,b,b,d, gemmule 

 birotulates ; c, face of rotule; e,e, long, spined dermal acer- 

 ates. Collected by Henry Mills. 



