Bibliograpliical Notices. 



497 



information regarding these singular creatures has hitherto been di- 

 spersed, in the form of detached papers, in the various scientific perio- 

 dicals, and the present instance is the first in which their descriptions 

 have been collected together and published in a full and explicit 

 manner. 



The author commences his work by a general view of the struc- 

 ture, physiology and geographical distribution of sponges in general, 

 and proceeds at some length to review the labours of his predeces- 

 sors on this subject, from the times of Aristotle and Pliny to the pre- 

 sent period. In this part of his subject we have the various and con- 

 flicting opinions of both ancient and modern naturalists, regarding 

 their animal or vegetable nature, examined and compared in a tem- 

 perate, clear and satisfactory manner ; and he concludes this able 

 digest of the labours of his predecessors with quoting the observa- 

 tion of Professor Owen, " that if a line could be drawn between the 

 animal and vegetable kingdoms, the sponges would be placed upon 

 the vegetable side of the line." But, our author observes, "We 

 shall possibly however arrive at an opposite conclusion, if, proceeding 

 in our inquiry, we follow the siliceous species insensibly gliding on 

 the one hand into the fibro-corneous sponge, filled with its mucila- 

 ginous fleshy slime, and on the other into the fleshy Tethya, in whose 

 oscula the first signs of an obscure irritability show themselves. 

 Sponges therefore appear to be true Zoophytes ; and it imparts ad- 

 ditional interest to their study to consider them, as they probably are, 

 the first matrix and cradle of organic life, and exhibiting before us 

 the lowest organizations compatible with its existence." 



In the chapter on " the discoverers of the British species," we have 

 a clear and concise account of the progress of their discovery, by 

 which it appears that forty species were described by Dr. Fleming 

 in his ' History of British Animals.' Our author however describes 

 fifty-six, being an increase of sixteen new species since the publica- 

 tion of Dr. Fleming's work. 



The systematic arrangement adopted is that of Dr. Fleming, with 

 some alterations and additions, and these have been carefully and 

 judiciously made. The author has again separated Spongilla from 

 Halichondria, and by this alteration, and by the adoption of new 

 genera, has increased the number from four, as described by Dr. 

 Fleming, to nine. 



The species have been described with much care, and additional 

 specific characters have been introduced where it has been found 

 necessary ; and the author has given a list of the synonyms to each, 

 so full and complete, as to render this portion of the work exceed- 

 ingly valuable. There are also extensive lists of habitats ; and the 

 latest information on the anatomy, physiology and habits of the va- 

 rious species treated of, and of the sponge tribe in general, has been 

 zealously collected and introduced up to the very latest period. 



The second part of the work, ' The British Lithophytes,' may be 

 considered in the light of a supplement to his ' History of the British 

 Zoophytes,' although the author by no means seems to consider them 

 as such. In the introduction to the subject he says, " The corallines 



