9;i0 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXVIII. 
The Alpheid, which clicks loudly when disturbed, is pale in colour and lives 
Diogenes-like in the tubular portions of the host, which are usually white- 
walled within, so that the colourless alpheid is indistinguishable when lying 
in wait in his lair for any small animals that may be tempted to enter for 
shelter. The little fish also uses the tubular region as a permanent home. 
In colour it is suffused pink over the whole body. It appears to lead a much 
freer life than its companion, the Alpheid, issuing forth to search for food fre- 
quently, but ready to retreat to his burrow on the least sign of danger. 
The other two of the usual commensals living with Solenocaulon, do not seem 
to make any particular use of the hollow and grooved branches though doubt- 
less they do derive some protective benefit from these facilities for hiding. They 
are however generally found crawling over the branchlets and among the po- 
lyps with which their colour assimilates perfectly. 
Hickson suggests that grooving and tabulation are due to the irritation of 
the tissues consequent upon the constant running to and fro of the Alpheid. I 
am inclined to think that the irritation is more direct and specific ; whether the 
nippers of the big chela have anything to do with it, say by pinching, is worth 
consideration when some one with the needful opportunity turns attention to 
this problem. 
Commensals of Gorgonids . — Gorgonids of many species are abundant 
on rocky and stony ground everywhere in shallow water round thejindian 
Fig. 1. — Wing-shells (Avicula radiata) commensal with^a 
sea-fan. (Original), 
