418 Bihliographical Notice. 



EIBLIOGKAPHICAL NOTICE. 



A Monograph of the Uorny Sponffes. By Robert von LEyDENFEtD. 

 London : published for the Royal Society by Triibncr and Co., 

 1889, 4to. Pp. 036, pis. 50. 



Dk. von Leni'ENFeld, after qualifying himself as an authority on 

 spongfes by studying them uuder the supervision of Prof. F. E. 

 Schulze, went to Australia and Xew Zealand, and spent some years 

 in making a collection of these organisms. In the seas bordering 

 these countries sponges with horny skidetons largely predominate, 

 and this fact induced the author to devote special attention to these 

 particular forms, with the primary idea of preparing a catalogue of 

 those inhabiting the Australian seas ; but finding that these 

 embraced a large proportion of the entire group known to science, 

 the project was extended so as to include the description of them as 

 a whole, and with this view the collections were brought to England 

 and worked out by the author in the British Natural-History 

 Museum ; and the large collection of these forms belonging to the 

 Museum, many of them new, were at the same time studied and 

 described in the present work, which has been published under the 

 allspices of the Royal Society. 



In the introductory part is a bibliographic list of publications 

 relating to sponges generally, both fossil and recent, which contains 

 1641 entries. This list is in the main similar to that previously 

 published by the author in 1886 in the ' Proceedings of the Zoolo- 

 gical Society,' and thus revised it may be considered as a fairly 

 complete list up to January 1888 of the literature which treats of 

 this class. 



The main body of the work is divided into two portions — an 

 analytical, devoted to the systematic description of all the known 

 horny sponges, which professes to give the plain empirical facts 

 relating to the anatomy, physiology, and classification of each genus, 

 without any reference to phylogeny or other hy])othesis ; and a 

 synthetical part, which treats of the anatomy of sponges generally, 

 and discusses their phylogeny, systematic position, and classification. 

 The author regards the cienus as the most important unit, and 

 endeavours to include in the characters of each a complete resume 

 of the comparative niorphology and physiology of all the species 

 embraced within it. The particular characters are thus summa- 

 rized : — (1) Historical Introduction, (2) Shape and Size, (;3) Colour, 

 (4) Surface, (5) Rigidity, (6) Canal System, (7) Skeleton, (8) His- 

 tology and Physiology, (9) Affinities of the Genus, (10) Statistics 

 of the Species, (11) Key to the Species and Varieties, and (^llM 

 Distribution. 



The author frankly acknowledges that sponges which possess the 

 common characteristic of a horny .skeleton cannot be considered as 

 foiniing a natural order, since certain groups are more nearly related 

 to other sponges which have not horny skeletons than to each other. 

 Four main groups of horny sponges are distinguished ; three of 

 these arc considered to be related to as manv distinct families of 



