210 Mr. A. Alcock on a case of Commensalism between a 



nor parasitic. It seems indeed on better grounds than those 

 of mere exclusion to be a very complete and unequivocal 

 instance of commensalism — complete because the reciprocal 

 benefits appear to be very clearly defined, and unequivocal 

 because it has been observed three times in places widely 

 distant from one another. 



§2. An Account of a Species ofStylactis alio ays found 

 associated with a Minous. 



On March 26th, 1889, there were trawled from 70 fathoms 

 off the Godavari Delta, on the Coromandel coast, on a bottom 

 o£ river-borne mud, two specimens of a small fish of the 

 Scorpsenoid genus Minous^ one of which was covered with a 

 fleshy colony of small polyps, which I then thought to be a 

 species of Podocoryne. The fish was described in the ' Journal 

 of the Asiatic Society of Bengal,' pt. ii. of vol. Iviii. for 1889, 

 as 3Iinous inermis^ sp. n. 



There occurred in the trawl at the same time ten specimens 

 of the Leucosine crab Parilia Alcocki, W.-M. ; five specimens 

 of the Portunid crab Goniosoma hoplites^ W.-M., var. ; many 

 specimens of the Penaiid Solenocera Hextiiy W.-M. ; and 

 about two dozen specimens of the gastropod moUusk Rostel- 

 laria delicatula, Nevill. 



The fleshy polyp found on Minous inermis was not present 

 on any of these ; and although most of the specimens of 

 Parilia were a good deal incrusted with foreign growths, the 

 only gymnoblastic Hydroid found on any of them was a 

 Perigonimus very closely related to, if not identical with, 

 Perigonimus vestitus, Allman. 



Minous inermis was not again met with until November A, 

 1891, when in a trawl hauled in 45 fathoms off the Malabar 

 coast, on a bottom of sand mixed with a shingle of broken 

 shells and echinoderm tests, nine specimens were taken, of 

 which all but one were thickly beset, especially round the 

 gill-opening and on the throat and in the axilla, with the 

 same fleshy colonies of the same polyp as was found incrusting 

 tlie type specimen of 1889. The haul was a big and varied 

 one, including among fishes similar in habitat to Minous 

 inermis (ground lovers), Minous coccineus, Pterois brachy- 

 ptera, Cuv. & Val., Uranoscopus crassiceps, Chanipsodon vorax, 

 Gthr.^ and two species of Platycephalus ; among ground- 

 living Crustacea several species of Leucosine crabs and two 

 species of Raninoids ; and several hundred living specimens 

 of six species of gastropod mollusks. 



