184 PROCEEDINGS OF THE ACADEMY OP [1884. 



June 24. 



Dr. W. S. W. RuscHENBERQER in the chair. 



Fifteen persons present. 



A paper entitled " Notes on the Geology and Natural History 

 of the West Coast of Florida," by Jos. Willcox, was presented 

 for publication. 



Some Modifications observed in the Form of Sponge Spicules. — 

 Mr. Edw. Potts remarked that whatever view we may prefer to take 

 as to the position which sponges occupy in the animal kingdom 

 — whether they are regarded as colonial flagellate monads with 

 Saville Kent, or with Haekel take a much higher place among the 

 metazoa, or perhaps, with still greater probabilit}', fill an inter- 

 mediate place between these, the formation and development 

 of the spiculas in both the Calearea and Silicea seem likely to 

 remain for a long time one of the most perplexing problems. 

 Many terms of this conundrum will readily occur to the mind of 

 any one who has worked in this field and observed the spiculae 

 from their earliest appearance to full maturity, and it is not the 

 design of the present communication to refer to them now more 

 particularly. 



An instance, however, in which a singular modification of 

 character has apparently been effected by the chemical condition 

 of the environment seems deserving of mention. Amongst the 

 sponges to which he had alluded in former communications as 

 encrusting certain old pipes, recently removed from the water- 

 works on the Schuylkill River, in Philadelphia, some portions 

 were much more deeply colored with rust than the others ; the 

 statoblasts, particularly, seeming to be mere pseudoraorphs of 

 their originals in iron oxide. Fragments of this character were 

 boiled in nitric acid, washed out and mounted for comparison 

 with other matter similarh' treated, but free from such dis- 

 coloration. 



The mature normal skeleton spicule of this sponge, Meyenia 

 Leidyi, is smooth, robust and shorter than that of any other 

 American species. Yer}'' rarely the fine line of the axial channel 

 is visible, but in the specimen under examination the size and 

 exterior appearance of the spiculse remaining as before, the hardly 

 noticeable channel has become a wide canal, open at both ends, 

 and occupying more than one-half the breadth of the spicule. 

 This does not occur merely in occasional instances, but universally 

 throughout the fragment of sponge so aflfected. (See fig. 5, 

 Plate IV.) 



The birotulate spicules of this sponge also arc short and of a 



