THE NAUTILUS. 39 
Twelve specimens of Astyris lunata from Wood Hole, Mass. 
weighed 0.095 gms. This would make one specimen weigh about 
0.008 gm. Reducing this to avoirdupois weight we have one shell 
weighing 0.000282 oz. 
The next example is Cerithiopsis Greenii—being the first of the 
species found in Canadian waters, i. e. from Prince Edwards Island. 
Ten specimens weighed 0.023 gm. or in ounces one specimen would 
weigh 0.000081 oz. 
Two sets of Odostomia seminuda were compared. The one being, 
like the above, the first found at Prince Edwards Island. The 
others came from near Woods Hole, Mass. It was found that the 
Canadians weighed each 0.000048 oz. while those from Mass. weighed 
each 0.000105 oz. The difference in size is noticeable without 
weighing. This proves that Mass. is a better place to live than 
Prince Edwards Island. The most interesting of all is New Eng- 
land’s conchological elephant, Skenea planorbis. The set weighed 
was found near Saco, Me. ‘The average weight of a specimen is 
0.000018 oz. At this rate it would require 56,700 to make an ounce, 
907,200 to the pound, and a ton would require 18,144,000,000. At 
the rate of five cents each, a pound would be worth $45,360.00. I 
am sorry to say I cannot supply them by the ton, or pound. 
After weighing, the writer became interested in size comparisons, 
and two species from the same region, i. e. Saco, were compared. 
The largest shell in my New England cabinet is Mactra solidissima, 
and the smallest Skenea planorbis. The Mactra weighs 174 oz. It 
would require 1,004,250 of Skenea to balance the one Mactra. The 
surface of the Mactra was reduced to a flat as near as possible, 
divided into small squares, and the Skenea was placed on the small 
square to estimate the comparative size. Dividing an inch into 
sixteen squares, Skenea would find room enough for 25 on each 
square, or 405 to the square inch. On the total surface of the 
Mactra (including both sides) there would be space enough for 
30,000 individuals of Skenea to rest comfortably. The above species 
are all marines and hence the comparisons are more interesting 
since conditions of life are similar. Much larger forms occur in other 
waters but the specimens selected represent the extremes of the New 
England area. I need hardly say that in commercial life these 
extremes are avoided and the medium sizes are of more economic 
value and popularity. 
