EMBRYOLOGY^ ETC. — DISTRIBUTION. Spoiig. 19 
indistinguishable. The flagellated chambers arise independently, and 
subsequently acquire connection with the canal system. They originate 
from mesoderm cells, marked out in the larva by their size, “formative 
cells,” which behave differently in different larvae, but a single formative 
cell never itself forms a chamber. At its first origin a chamber is an 
intercellular lacune. 
The author points out the resemblance between this asexual develop- 
ment and the egg development of many siliceous Sponges. By the light 
of Woissmann’s theory ho would regard the gommule-ccll as a true germ- 
cell, in which none of the germ plasm is transformed into ovogenotic 
plasm, and which pursues the parthenogenetic course of development. 
The gemmule development of Tedania is quite similar to that of 
Esperella. 
The egg of Tcdanione has a total segmentation, resulting in a solid 
morula, and the free larva is a solid oval body, completely covered with 
columnar ciliated cells. Ilircinia also forms a morula. The maturation 
of the egg in these two Sponges (p. 518) is similar to that described by 
Fiedler in Spongilla. 
c. Physiology and Biology. 
Jennings discusses the manner of growth and habits of the Boring 
Sponge, Alectona miliar i (Carter). 
Keller (1, 2) describes the influence of life conditions upon the 
secretion of spongin, and its employment to build up the skeleton. [See 
under “Anatomy, Histology, &c.”] 
Weber (2) describes three cases of symbiosis in Sponges: (1) between 
Ephydatia fluviatilis and an Alga, Trentepohlia spongophila ; (2) between a 
Jlalichondria and an Alga, Struvea delicatula ; and (3) between a Reniera 
and an Alga, Marchesettia spongioides. 
For the Physiology of Spongillidct’, sec Weltner. 
III. — DISTRIBUTION . 
A.— FAUNISTIC. 
Canada and Newfoundland ( Spongillidce ) ; Mackay. 
W. Coast of Ireland ; Hanitscii. 
Oceanic Coasts of France ; Tofsent (2). 
Luc, Sponge fauna ; id. (6). 
Roscoff, Sponge fauna ; id. (4). 
Bergen, Sponge fauna ; Brunchorst. 
Canaries and Senegal ; Tofsent (1). 
Adriatic ( Calcar ea ) ; von Lendenfeld (1,4). 
Red Sea ; Keller, (1) pp. 349-356. Chalinidaz predominate. No 
Clathriai or Espericc occur, also no species of Geodia. The Calcarea are 
feebly represented, and there are no Hexactinellida. Tho only species 
