492 E. A. MINCHIN. 
210—217, Taf. viii, fig. 4; ix, figs. 27—87). The author 
divides the sponge into four forms, which he terms A, B, C, 
and D, rejecting Haeckel’s varieties, ‘‘since these forms 
appear to arise one from the other in the course of the post- 
embryonal development.’ Form A consists of a mass of 
anastomosing tubes, 1—5 mm. in diameter, the walls of which 
have pores and contain numerous stellate connective-tissue 
cells, but no large granular elements ; the endoderm forms a 
single layer. In Form B the tubes are only 0°3—1'5 mm. in 
diameter, and form a flat spread-out creeping network. Pores 
are rare, and the “ zwischenschicht” (mesogloea) contains, 
besides stellate cells, large granular, spherical or irregular 
cells; the endoderm is many-layered. Form C is similar 
externally to Form B, but has no pores in its walls; the same 
large granular cells occur as in B, and the endoderm is many- 
layered but more closely packed than in the latter form. 
Form D consists of a flat network of trabecule, 1°5—3 mm. 
thick, in which no pores were to be found; in the mesoderm 
large granular cells were not observed, and the endoderm fills 
up the interior of the tubes, leaving only irregular lacunes. 
All the forms agree in having no oscula visible to the naked 
eye, and are reticulate Auloplegmas. The author believes 
that the many-layered endoderm and the closing of the pores 
is connected with the ripening of the eggs (see p. 217). Dr. 
von Lendenfeld has made a considerable advance in rejecting 
Haeckel’s varieties, but is nevertheless far from a correct 
explanation of the different forms, which are nothing more 
than different states of contraction of the sponge. Thus his 
fig. 30 (Taf. ix), representing a section of Form D, is in all 
essentials completely similar to my fig. 14, which is taken 
from a series of sections through the piece of sponge shown in 
fig. 5. This sponge, as above described, when first collected 
was- like the specimens shown in figs. 1 and 2, and after 
completely contracting, frequently expanded again to this 
form. I have recently observed a similar contraction in 
another sponge, an Ascon of a beautiful orange-red colour, but 
with the spiculation of Ascetta primordialis, which when 
