Dr. J. E. Bowerbank on the Spongiacbe. 145 



iiiutisina, Ecionemia, Alcyoncellum, Polymastia, Halyphysema, 

 Tethea, Halicnemia, Dictyocylindrus, Phakellia, Microciona, Ily- 

 meraphia, and Hymedesmia. 



The second suborder consists of spiculo-membranous sponges ; it 

 consists of one genus, Hymeniacidon. The third has spiculo-reticulate 

 skeletons ; it contains four genera, Halichondria, Hyalonema, Tso- 

 dictya, and Spongilla. The fourth suborder has spiculo-fibrous 

 skeletons ; it contains two genera, Desmacidon and Raphyrus. The 

 fifth suborder has compound reticulate skeletons ; it has but one 

 genus, Diplodemia. The sixth suborder has solid siliceo-fibrous 

 skeletons ; it contains one genus, Dactylocalyx. The seventh sub- 

 order has canaliculated siliceo-fibrous skeletons, and contains one 

 genus, Farrea. 



The third order, Keratosa, is also divided into seven suborders. 

 The first, consisting of solid non-spiculate kerato-fibrous skeletons, 

 is represented by one genus, Spongia ; the legitimate type of the 

 genus being the cup-shaped and finest Turkey sponges of commerce. 

 The second suborder has solid semi-spiculate kerato-fibrous skele- 

 tons ; it contains at present but one genus, Halispongia ; the types 

 of which are the coarse massive sponges of commerce from the West 

 Indian Islands. The third suborder has solid, entirely spiculated 

 kerato-fibrous skeletons ; it has one genus, Chalina : the type of 

 this genus is one of the commonest of the British sponges, Halichon- 

 dria oculata of Johnston. The fourth suborder is characterized by 

 having simple fistulo-.fibrous skeletons ; it contains one genus, 

 Verongia. The fifth suborder contains sponges which have com- 

 pound fistulo-fibrous skeletons, and is represented by the genus 

 Auleskia. The sixth suborder consists of sponges having regular 

 semi-areno-fibrous skeletons, and is represented by the genus Stema- 

 tumenia. The seventh suborder has irregular and entirely areno- 

 fibrous skeletons ; it is represented by the genus Dysidea. The 

 whole of these genera (those previously established as well as the new 

 ones proposed by the author) have been characterized in accordance 

 with their anatomical structures. 



The author concludes his paper with a dissertation on the discri- 

 mination of species, and a general review of those portions of the 

 organization that may be applied with advantage to their scientific 

 description, — the principal sources for this purpose being : — 1st. 

 The spicula. 2nd. The oscula. 3rd. The pores. 4th. The dermal 

 membrane. 5th. The skeleton. 6th. The interstitial membranes. 

 7th. The intermarginal cavities. 8th. The interstitial canals and 

 cavities. 9th. The cloacal cavities. 10th. The sarcode ; and 1 lth. 

 The ovaria and gemmules. And, finally, directions for the examina- 

 tion and preservation are given, with a few examples of the mode of 

 specific description proposed by the author. 



Ann. $ Mag. N. Hist. Ser. 3. Vol. x. 11 



