PROCEEDINGS OP THE MALACOLOGICAL SOCIETY. 63 



When found, the shell was complete to the first break in the band on the 

 body whorl. In captivity it quickly completed its shell, but made an incom- 

 plete lip — a trace of the colouring being seen on the inner lip. It then 

 developed during the summer months the abnormal growth. It is interesting 

 to note the weakening of the band at the beginning of captivity ; and also 

 that a trace of the band is to be seen on the abnormal growth when held 

 to the light, and that the growth is lined with nacre. 



Mr. Woodward also exhibited sectioned specimens of H. nemoralis 

 from. Dogs Bay Connemara and from Huccombe, South Devon, 

 for comparison with the Caldey specimen. 



By Dr. Boycott, a literary exhibit from " Pearson's Magazine " 

 showing the use made of the locality of a well-known but uncommon 

 shell in the tracing of a criminal. 



ORDINARY MEETING. 



Friday, 9th June, 1922. 

 A. S. Kennard, F.G.S., President, in the Chair. 



The following communications were read : — 



1. Notes on several forms of the genus Poecilozonites. By 

 Lieut.-Col. A. J. Peile. 



2. On the Chiton Fauna of Australia. By Edwin Ashby, F.L.S., 

 M.B.O.U. 



[Abstract.] 



Mr. Edwin Ashby showed a very fine collection of Polyplacophora repre- 

 senting the Chiton fauna of Australia. He explained that the Pacific Coast 

 of the American Continent and Australia were competitors for the position 

 of the Metropolis of the world's Chiton fauna. At the present time Australia 

 holds the premier position in number of species, but in both regions there 

 are still no doubt many new forms awaiting discovery. 



Some very large chitons were shown, from 4 to 5 inches in length, but it 

 was stated that for beauty of design and delicacy of tracery the sculpture of 

 the rare and minute members of the genus Acanthochiton far surpass the 

 sculpture of the larger forms. The habits of the various forms were referred 

 to, and it was shown that many were only found at quarter-tide or half- 

 tide, as the case may be, their habitat being restricted to that particular 

 depth of water, so that on searching only 6 inches or so deeper that species 

 would not occur at all, but would be replaced by another species. This 

 regularity of depth distribution has led some zoologists to define the various 

 zones in which certain marine life is to be found by the respective chitons 

 that inhabit that particular depth of water. 



Mr. Ashby then referred to some strange organs he had described under 

 the name of " Spearhead spicules ", occurring consistently on the girdle of 

 Loricella angasi, H. Ad. & Ang. On this species these coarse branching 

 bristles are surmounted with swollen heads shaped like the head of a spear, 

 and white in colour, whereas the stalks are brown. These spear-headed 

 bristles occur round the girdle opposite the finger-like processes that fringe 

 the girdle. Smaller " spear-heads " jv^ere pointed out pushing their way 

 through the girdle scales down the centres of these finger -like extensions of 

 the girdle. 



The speaker then showed organs somewhat analogous to these, which he 

 had discovered on the girdles of the representatives of the genus Kopionella, 

 Ashby. He pointed out that in both genera these organs were evidently 

 deep seated, and while the exact purpose they serve in the life of the animal 

 is not yet known, he suggested that they probably have some connection 



