Mr. J. Hogg on the Horny Sponges. 5 



Also, it becomes me to correct the following passage from 

 that Journal : — " Dr. Grant's observations were limited prin- 

 cipally to the British species of sponge having siliceous or 

 calcareous spicula ; the true horny species not having up to 

 that period been found on our coast. Sowerby, in his ' British 

 Miscellany/ has subsequently figured the Spongia pulchella 

 obtained from the southern and western coasts of England." 

 Now Dr. Grant published his observations in the ' Edin- 

 burgh PhilosophicalJournal' for the years 1825, 1826, 1827, 

 whereas Sowerby's * British Miscellany,' vol. i., was published 

 long before — in fact, in the year 1806; in which volume, at 

 p. 87, Sowerby described the S. pulchella as a new species, 

 specimens of which had been sent to him by Mr. Brown from 

 Ireland about the year 1800, and by the Rev. Hugh Davies 

 from North Wales in 1802. I may here add, that I have 

 found this beautiful species on the coast of Durham, where 

 however it is rarely met with. Having already observed upon 

 the similarity of the spicula with 7'aphides^, I perfectly coin- 

 cide with Prof. Jones in accounting the crystalline needle-like 

 particles which so abundantly occur in many sponges, as 

 being analogous to and most resembling those crystalline se- 

 cretions of plants ; and I must confess that I do not see any 

 facts detailed in the papers of Mr. Bowerbank to lead me to 

 alter my opinion respecting the vegetable nature of sponges. 



The objectionable word ' keratose' has, I am glad to see, 

 called forth a just remark from the Editor. 



I have been in the habit of using the word ' subcorneous ' in 

 my own attempted an'angement of the SjJong'KB, in which I have 

 distributed many species without adopting the new generic 

 names of Calcispongia, Grantia, Halichondria, Halispongia, 

 Tethya, Tethium, part of Alcyonium of Lamarck, etc. ; since I 

 thought it better to consider the whole under the new genus 

 Sjjongilla, and the old genus Spongia of Linnaeus and Mon- 

 tagu. 



The Order SpongicB I some months ago separated for my 

 own convenience into the following divisions : — 



Division I. SponyicB Subcornece. The Subcorneous Sponges. — Having 

 fibres of a somewhat horny substance without any spicula. 

 Example of a British species : S. pulchella (Sow.). 



Division II. S. Subcoriieo-silicece. The Subcomeo-siliceous Sponges. 

 — Fibres composed of a somewhat horny substance with nume- 

 rous siliceous spicula. 

 No species hitherto discovered in Britain. 



Division III. S. Subcartilayineo-calcarice. The Subcartilagino-calca- 

 * See Linn. Trans., vol. xviii. p. 398. 



