478 Records of the Indian Museum. [Vo1L. XI, 1915.] 
Both these Clionids are known only from specimens taken 
in a single haul of the ‘ Investigator’s’ net, and it is impossible 
therefore to say much about their enemies. We know, however, 
that T. investigatoris is attacked by C. tnvestigatrix, and I have 
not been able to find any example of the latter that is drawn out 
into a sufficiently fine filament to make its way into a gemmular 
chamber of the Clionid. 
The information conveyed in the foregoing biological notes 
may be summarized as follows :— 
1. The Clionidae are liable to be attacked in their burrows 
by a large number of small sponges belonging to several different 
families. 
2. The majority of these invading species are known to 
exist also as ordinary encrusting forms but in a few instances (e.g. 
that of Coppatias investigatrix) the sponge has possibly become a 
pure parasite. 
3. In most cases the invader merely occupies the burrow of 
the Clionid, which it thrusts before it, but in some instances it is 
possible that it actually engulfs and digests the proper occupant. 
4. Different species of Clionidae protect themselves against 
invasion in slightly different manners, but all secrete a horny coat 
where the invader comes in contact with them. 
5. The production of transverse diaphragms in the galleries 
of the Clionidae is possibly a means of protection against invading 
sponges, especially in the case of C. mucronata, in which these 
diaphragms are of an unusually elaborate nature. 
6. The production and elaboration of gemmules in the 
Clionidae is perhaps another means of defence against similar 
enemies, particularly in the case of the deep-sea species C. annult- 
fera and T. tnvestigatoris. 
7. The cases of invasion investigated represent only a small 
proportion of those in which similar phenomena occur. 
le 
