PEE PACE. IX 



tlie issue of the volume in which he found them, 

 whereas they had really been published elsewhere many 

 years previously. The references now given will supply 

 this omission, and what has been said will enable 

 naturalists to understand the principles on which the 

 author laboured. 



The editor has not given any synonymy or re- 

 ferences regarding the Calcareous Sponges in the body 

 of the work ; to have done this would have necessitated 

 a complete revision of the species, and he refers the 

 student to the Appendix, where will be found a sum- 

 mary of the views of Haeckel. 



With respect to the habitats to which the editor's 

 own initial (N.) is attached, indicating thereby that the 

 specimens referred to have either been collected by 

 himself or are in his cabinet, he has thought it 

 advisable only to record the localities of such speci- 

 mens as have actually passed through Dr. Bowerbank's 

 hands and been identified by him. It must be under- 

 stood, however, that this remark only applies to those 

 habitats which have the initial N. after them ; not 

 necessarily to such as are recorded on the authority of 

 other naturalists, unless either the record is in inverted 

 commas without any name after it, thus showing that 

 the note is Dr. Bowerbank's, or it is expressly stated 

 that he had determined the specimens. 



A large number of the localities to which the 

 editor's initial is attached will be found to be situated 

 in the counties of Gralway and Mayo, where a remark- 

 ably fine collection of sponges was obtained during a 

 scientific expedition which Mr. D. Robertson, of Glas- 



