308 ORTMANN—CORRELATION OF SHAPE AND 
This can be tested, of course, only in such forms which have a 
wide distribution, and are found both in large and small rivers. I 
have measured a number of such, but did not find any evidence for 
our law in the following cases. 
Elliptio dilatatus (Raf.)—Distribution tremendous, equally 
abundant in large rivers and small streams: but no trace of the law 
observed. 
Strophitus edentulus (Say)—The same wide distribution in all 
kinds of streams, but no evidence of the law. 
(It should be noted that no species belonging to the subfamily 
Anodontinas has shown, so far, any evidence of submitting to this 
law.) 
Ptychobranchus fasciolare (Raf,)—The same holds good for 
this species as for the two preceding ones. 
Actinonaias carinata (Barn.) (== Nephronaias ligamentina) .— 
Although not going into the smallest headwaters, this species is 
found in smaller and larger rivers, but no change of obesity is 
observed, 
Euryma recta latissima (Raf.)—Has a very wide distribution 
from the large rivers well up into the headwaters, but is remarkably 
uniform in obesity. 
Lampsilis siliquoidea (Barn.) (= luteola).—Practically ubiqui- 
tous in the interior drainage (although missing in the upper Ten- 
nessee). No relation observed between size of stream and obesity, 
although the shell is very variable. 
Lampsilis fasciola Raf. (= multiradiata).—Practically every- 
where in the interior drainage, but obesity not responding to station. 
Truncilla triquetra Raf.—Of wide distribution, and in streams 
of various size, but without marked change in obesity. 
Truncilla capseformis (Lea)—Widely distributed and common 
in the upper Tennessee region, found in small creeks and large 
rivers, but uniform in the convexity of the valves. 
In addition it should be remarked that in none of the species be- 
longing to the Atlantic drainage this law has been observed to exist. 
This is most evident in the common Elliptio complanatus (Dillw.). 
This is found practically everywhere, in large rivers as well as in 
