EXPLANATION OF PLATE XXXIV. 
Bigs 0, 02% 
vestigatrix. 
1. A young Coppatias that has just made its way into the 
burrows of the Thoosa in a Gastropod shell, seen from below 
(Ponto): 
2. Portion of an older sponge of the same species in con- 
tact with the Thoosa, seen from the side (xX 65). 
A. A’ = the Thoosa: B =the Coppatias : S = Gastropod shell 
in section: c = cavity from which calcareous matter has been re- 
moved by acid: e #.—exhalent papilla of the Thoosa: h.c.=horny 
coat secreted by the Thoosa. : 
In fig. 1 the young invading sponge has apparently made its way through an 
inhalent papilla of the 7hoosa, which is represented by a confused mass of spicules 
(A’). The adjacent exhalent papilla (A) is distorted and greatly enlarged. 
Thoosa investigatoris attacked by Coppatias in- 
Fig. 3,—Cliona viridis attacked by Rhabderemia prolifera. 
= C. viridis; B = Rh. prolifera: c = cavity from which 
calcareous matter has been removed by acid: c’ = passage be- 
tween two calcareous masses coated with the sponge. 
Figs. 4, 4a.—Chondrilla distincta attacking Cliona ensifera. 
4. A mass of the Chondrilla sending out tentacle-like branches 
to envelop the Cliona in dead coral (X 75). 
4a. A single tentacle-like branch more highly magnified 
(X 255). 
A =C. ensifera: B, B’=Ch. distincta: C= cavity from which 
calcareous matter has been removed by acid: # = tentacle-like 
branch. 
At B’ a tentacle-like branch has grown out from behind over the surface of 
the Cliona, which it is enveloping. 
