4 Spong. 
XVII. SPONGE. 
INTRODUCTION. 
I. The Zoological Record of Sponges for 1901 includes seventy-four 
publications, not counting abstracts and reviews, but of this total, one 
dates from 1897, one from 1898, two from 1899, eight from 1900, and one 
memoir published in 1902 [Whitelegge (65)] has been included by the 
Recorder, since it seemed unadvisable to separate it from the work to 
which it was merely supplementary. There remain 61 titles belonging 
strictly to 1901. 
II. In Biology very great interest attaches to the splendid monograph 
of the Euplectellidce of Japan by Ijima (29), and to his investigations upon 
the structure and development of these sponges. Attention may be 
drawn especially to his discovery that in the dermal layer of Hexacti- 
nellids there is no distinction between epithelial and parenchymal strata, 
the intercellular ground-substance being totally undeveloped. In this 
point the Hexactinellida contrast with all other known sponges, and stand 
on a lower level of differentiation than the Calcarea or Demospongiae. 
The point is also one which has a very obvious bearing upon the “ meso¬ 
derm” question in sponges. Very interesting also are Ijima’s observations 
upon the larvae of Hexactinellids and their derivation from congeries of 
archseocytes, a point in which he supports H. V. Wilson’s much criticized 
views with regard to “ gemmule-larvse.” According to Maas (38), Tethya 
also is a sponge in which reproduction by gemmules formed from aggre¬ 
gations of archaeocytes has replaced the normal method of sexual repro¬ 
duction and larval development. The observations of Maas (37) upon the 
formation of asters in Tethya by fusion of minute tetraxons may fairly 
be termed sensational, and furnish an unexpected clue to the relation of 
Tethya to Tetraxonid ancestors. Another memoir of phylogenetic interest 
is that of Schrammen (50), in which a polyphyletic origin is asserted for a 
group apparently so homogeneous as the Lithistida. Of other works in this 
section, the investigations of Butschli (9) upon the minute structure of 
calcareous and siliceous spicules may be noted. The studies of Petr (44) 
upon the parenchymal spicules of Spongillince , are doubtless of interest to 
those who can understand the language in which they are given to the 
world. In the economic section, Seurat (52) furnishes a very useful 
summary of knowledge relating to sponges of commercial importance. 
III. Under the heading Geographical Distribution Topsent (59) com¬ 
pletes our knowledge of the sponge-fauna of the coast of Algiers, makes 
important contributions (60) to our knowledge of Antarctic sponges, 
and describes some new forms of Hexactinellids (58) from the Azores. 
Whitelegge’s studies (64 & 65) upon the sponge-fauna of New South 
Wales are very valuable, and Arnesen (5) gives a list of the Calcarea of 
Norway. Useful local lists are given by Kingsley (31), and Whiteaves 
(63). Weltner (62) revises and completes our knowledge of the fresh¬ 
water sponges of Celebes. In palaeontology the most important works are 
those of Malfatti (40), Schrammen (50), and Vinassa de Regny (61). 
IV. The contributions on the side of Systematic do not comprise any 
novelties so remarkable, or monographs so voluminous, as those recorded 
for the previous year, but in every group the additions to our knowledge 
are numerous. Topsent (56-60), is one of the foremost contributors, and 
describes a number of new Hexactinellida and Monaxonida. Whitelegge 
(64 & 65) has done most useful work in reexamining the types of 
Australian sponges and correcting the extraordinary errors contained in 
the original descriptions. Ex fumo dare lucem should be his motto. 
Schrammen’s work (50) on Cretaceous Lithistida continues his previous 
studies on the Choristida, and since he has now been able, as he states, to 
consult Sollas’s Challenger Monograph and other memoirs of importance, 
