96 THE HAMILTON ASSOCIATION. 
MALACOLOGY. 
(Continued April 27, 1900.) 
BY COL. C. C. GRANT. 
TRIGONID#. 
The sole survivors of this ancient family are found in 
Australian waters. Some naturalists hold there are three 
distinct species dredged there, while others consider these are 
merely varieties, since the internal color of the shell (purple or 
golden) is hardly sufficient for such a distinction. Recent 
dredging proves a considerable difference may exist not pre- 
viously suspected. Take for instance the Cyprea Tigris of 
Linnzus—a naturalist in the United States—obtained off the 
Japanese coast lately no less than fifteen tiger cowries with 
well-marked color varieties. They vary, he states, from very 
light cream body color, sparsely blotched with brownish black 
spots, to others which are clouded with velvety brown, like 
precious tortoise shell. Mere varieties are probably often 
mistaken for that ill-defined term ‘‘species,’”’ referred to ina 
paper by Mr. Moffat, which has already appeared in our pro- 
ceedings. 
The modern Trigonia appears to be an exceedingly active 
mollusc. Mr. Stutchbury mentions he placed one on the 
gunwale of his boat, which leaped overboard, clearing a ledge 
four inches high. Woodward states fossil specimens are found 
ranging from the Trias to the chalk, and are not discovered in 
Tertiary rock. Perhaps this may be owing to the imperfection 
of the record. He refers to Lyrodesma, of the .Cambro- 
Silurian drift of our lake shore, Amphidesma and others, and 
concludes their generic character has yet to be discovered, and 
the epidermal layer of the recent shell, with rts nucleated cells, 
is a beautiful object under the microscope. : 
