510 HYATT'S REVISION OF THE 



as is perhaps possible, the objection might be made that it is altogether too cumbersome for 

 the purpose of labelling collections for exhibition in Museums, and miglit lead to some con- 

 fusion in the use of the names here proposed. I therefore append a list below, made out 

 according to the usual method, every sufficiently distinct form being labelled as a different 

 species, so that one may have a choice. 



a ■ jyy ■ 1- T- \ Sponqia Adriatica Schra. , . -.r i-^ 



SponcjiaofficmahsUnn.= j ^ ,/ ^»«™ere«sis Schm = '"^■■^P^"^*^' ^^^^^^'^''''«'^^«- 



" mollissima Schni. = variety molUssima (Levant sponge and Turkey Cup). 



" tuhulifera Duch. et Mich. = species tubulifera. 



" discus Hyatt. 



" lignea Hyatt. 



" (jraminea Hyatt. 



" equina Schm. 



" gossyjnna Duch. et Mich. = sub-species gossypina. 



" meandriniformis Duch. et Mich. = sub-species meandriniformis. 



" cerebriformis Duch. et Mich. = sub-species cerehriformis. 



" agaricina Pall. = Sjiongia Zimocca Schm. = sub-species Zimocca. 



" dura Hyatt = sub-species dtira. 



" punctata = sub-species p^mcto^a. 



" corlosia Duch. et Mich. = sub-species corlosia. 



u vermiculata Duch. et Mich. 



" Coohii Hyatt ^ sub-species Cookii. 



" moUiata Hyatt = sub-species molliata. 



" lapidescens Duch. et Mich. 



" dentata Hyatt = sub-species denfata. 



" Mauritiana Hyatt = sub-species Mauritiana. 



" tectoria Hyatt =^ sub-species tectoria. 

 I have found myself entirely at a loss in the attempt to use the microscopical structure 

 and arrangement, or size of the fibres in the descriptions of the species and varieties. The 

 number of illustrations necessary in order to show the variations in one single colony, and 

 in any one of the better represented species would have filled several plates. The expense 

 and doubtful utility of attempting to delineate fully, structures so evidently subject to local 

 modifications, and the necessity of a strict economy in the Society's publications, caused 

 the abandonment of all figures of the skeletal structure in order to secure a more complete 

 representation of the constant characteristics of the external surface. 



The series of slides, however, prepared by Mr. Crosby, Assistant in the Society's 

 Museum, and myself, repi'esent many varieties, and from these, and others of a more tem- 

 porary character, have been taken the remarks with regard to the microscopical structure 

 of the skeletons which accompany the specific descriptions. 



