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Bibliographical Notice . 
BIBLIOGRAPHICAL NOTICE. 
A Monograph of the Horny Sponges . By Robert yon Lendenfeld. 
London : published for the Royal Society by Triibner and Co., 
1889. 4 to. Pp. 936, pis. 50. 
Dr. yon Lenhenfeld, after qualifying himself as an authority on 
sponges by studying them under the supervision of Prof. F. E. 
Schulze, went to Australia and New Zealand, and spent some years 
in making a collection of these organisms. In the seas bordering 
these countries sponges with horny skeletons 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 
auspices 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 hypothesis ; and a 
synthetical part, which treats of the anatomy of sponges generally, 
and discusses their phylogeny, systematic position, and classification. 
The author regards the genus as the most important unit, and 
endeavours to include in the characters of each a complete resume 
of the comparative morphology 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 (12) 
Distribution. 
The author frankly acknowledges that sponges which possess the 
common characteristic of a horny skeleton cannot be considered as 
forming 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 are considered to be related to as many distinct families of 
