spongle. 
G 8 pong. 
japonica ), which is characterized by sexradiate symmetry, the six chief 
excurreiit canals being constantly six in number. 
Lendenfeld (19) describes the anatomy and histology of Dendrilla 
cavernosa, n. sp., and Raphyrus hixonii, n. sp. The “vestibule” of the 
former is closed by a poriferous membrane which merits detailed descrip- 
tion. Ectodermal epithelium occurs on both inner and outer faces, 
' investing a gelatinous matrix containing cellular elements ; the pores are 
very short, conical tubes, widest outwards, at their inner ends a number 
of fusiform cells radiate from the circular margin inwards towards amoeba- 
like cells, from which fine processes extend outwards in every direction. 
Lendenfeld regards the latter cells as ganglionic, the former as sensitive. 
Farther away from the pore fusiform muscle cells and amoeboid wandering 
cells occur, and beneath the general epithelium gland cells. 
Lendenfeld (20) also describes the complete replacement of the soft 
parts of Dactyl ochalina australis , n. sp., by an Alga (Floridean ?). 
Ridley & Dendy (4) describes the structure of Proteleia sollasi , a 
Suberite of .considerable interest, as possessing small anchor-like 
spicules, which project from the cortex like those of some Tetractinellid 
Sponges. 
• Ontogeny and Piiylogeny. 
Heider (12) gives a full and circumstantial account of the develop- 
ment of Oscarella lobularis from the blastula stage to that of the 
Rhagon : — 
(«) The blastula. — In this stage the larvae escape from the parent in 
great numbers during the months of October and November, usually at 
night. They are egg- or pear-shaped, but undergo transitory changes of 
form, sometimes shortening and broadening, at others lengthening out. 
Fpr days they swim about freely, now and. again attaching themselves to 
fixed objects or the surface of the water. 
(b) Histology of the blastula- -It consists of a single layer of long pris- 
matic flagellated cells, which enclose a central cavity, filled with a non- 
cellular , granular, albuminoid fluid. The cells consist for the greater 
part of their length of- coarsely granular and pi gmented endoplasm ; the 
remaining distal part is a clear, or sometimes faintly granular, exoplasm, 
which is more. hyaline and refringent at the surface than deeper in. This 
is produced into a collar, which does not differ from that of the collared 
cells of the flagellated chambers of the adult except in being somewhat 
shorter. From the middle of the end of the cell a long flue flagellum 
extends, which can be traced inwards into continuity with a sheath of 
somewhat denser plasma which surrounds the nucleus. Besides the pris- 
matic cells, others of a pear- or flask- shape sparingly occur ; these are 
devoid of a flagellum, but provided with exceptionally high collars. The 
cells of the blastula do not lie in actual contact, but are separated by a 
small quantity of intercellular substauce, probably of the same nature as 
the gelatinous fluid of the central cavity. 
(a) The free-swimming gastrula stage . — The posterior red-coloured end 
of the blastula is, as a rule, invagiuated within the yellow anterior moiety; 
