ANATOMY EMBRYOLOGY. 
Spong. 11 
under the name Crambe harpago amongst the Desmacidincc, as possessing 
chelae which are not accidental, as Lendenfeld thinks. The specific name 
then given by himself should be dropped, and the Sponge called Crambe 
fruticosa , 0. S. 
Vosmaer & Pekelharing (63) in their paper say “ Sollas’s membrane 
does not exist.” The choanocytes stand quite free, and touch each 
other only at the very base. Then follow the opinions of other authors, 
namely Sollas, Dendy, Lendenfeld, Bidder, Delage, and Minchin, and a 
critical analysis of these various opinions. Finally the methods used in 
preparing the material are given. The species examined were : Hali- 
chondria panicea , Spongilla lacustris , and Sycon ciliatum. [Compare 
Bidder (3) and Lendenfeld (24), p. 163.] 
Weltner (65) has an extensive report on the work done in Spongology 
during the years 1888-1891. The report is arranged under the follow- 
ing headings: List of Papers, pp. 161-175 ; General, pp. 175-177; 
Methods, pp. 177-179 ; Sponge Culture, pp. 179 & 180 ; Anatomy and 
Histology, pp. 180-193 ; Nomenclature of Spicules, p. 193 ; Physiology, 
pp. 194-199 ; Ontogeny, pp. 199-207 ; Phylogeny, pp. 207-210 ; 
Systematic and Faunistic, pp. 210-255 ; Fossil Sponges, pp. 255 & 256. 
b. Embryology. 
Delage (11) claims the priority of having discovered the formation of 
the epidermis from the cells of the inner layer, and that the ciliated cells 
travel to the inside. 
Maas (29) gives a contribution to the doctrine of the continuity of the 
germ-plasm. There are two kinds of cells forming the “ mesoderm ” of 
the adult Sponge, (1) fine granular cells possessing oval nuclei with a 
delicate network of chromatin ; (2) cells with coarse granular proto- 
plasm and vesicular nuclei, the amoeboid wandering cells, which give rise 
to the sexual elements. Both kinds of cells can be traced back through 
all the larval stages to the maoromeres of the segmenting embryo. But 
whilst the former cells are differentiated descendants, the amoeboid cells 
are the unaltered descendants of the macromeres. In other words : we 
can prove a direct derivation of the germinal cells from the ovum, since 
after the subtraction of all somatic specialized elements, there remains a 
number of undifferentiated elements, the primary sexual cells. 
Maas (30) has an important paper on the embryonic development and 
metamorphosis of the Cornacuspongice. He studies — 1st, The metamor- 
phosis (reversion of layers, &c.) in types of all the families of Cornacu- 
spongice ; 2nd, The formation of the larva from the ovum, in order to be 
able to homologize the same with larvae of other groups of Sponges, and 
to support the view that the sponge- organism arises from two germinal 
layers only, although the adult shows three strata. Maas studied the 
development of Chalinula as type for the Homorrhaphidce , Gellhis for 
the Heterorrhaphidce , Myxilla for the Desmacidonidce, Axinella for the 
Axinellidce. Certain stages in the development of Hircinia , Euspongia , 
