1884.] NATURAL SCIENCES OP PHILADELPHIA. 209 



when divested of the sarcode, which often has a particular color, 

 there is absolutely nothing left but the horny fibre covered with a 

 heterogeneous assemblage of foreign objects, viz., sand, frag- 

 mentary sponge-spicules and other microscopic bodies, which 

 vary in amount and kind with those which are most plentiful in 

 the locality where the sponge may be growing, if we except the 

 general form which the skeletons composed of this fibre may 

 retain. 



The Suberites par escellence, too, like the Hircinias, require a 

 similar treatment, for here the skeletal spicule, being for the most 

 part simply pin-like, is so similar and so slightly varied in form, 

 that, in most instances, this alone would be insufiicient for dis- 

 tinction. However, the skeletal spicule is often accompanied by a 

 flesh-spicule of a spini-spirular or other form, which lessens the 

 difficulty; but they can seldom be seen without mounting a 

 microscopic fragment in balsam, when the transparency renders 

 them (if there are any) plain, which the wet sarcode previously 

 rendered obscure. This should be done with all the specimens 

 above mentioned, as it involves an amount of time which I now 

 have not at my disposal ; hence can only recommend the student 

 to consult my initiatory attempt to do this in the " Annals " of 

 1882 ("West Indian Sponges," etc., vol. 9, p. 349, etc., pi. xii, figs. 

 25-30). 



See also, for the group Donatina and species Donatia lyncurium, 

 "General observations " (lb. ib., p. 358, etc.). 



In m}' division of the Echinonemata, the first groups of the 

 families Ectyonida and Axinellida respectivelj', viz., " 1 " and 

 " 6 " i. e. " Pluriformia " and " Multiformia " are merely pro- 

 visional terms for including a vast number of species which here- 

 after will have to undergo description, illustration and division, 

 when they shall have been usefully collated, etc., after the manner 

 already mentioned, but so much time, taste, labor and opportunity 

 will be required for this, that many years must pass before it even 

 approaches completion. 



The number of species of sponges that exist and have still to 

 be discovered has been chiefly foreshadowed to me by the dry 

 specimens in the British Museum, upon which m}^ proposed 

 " Classification " has been based, but cannot be put forthwith 

 any certainty under such circumstances, more especially the sub- 

 division of the orders. 



