28 
carnivorous or flesh-eating species it has either a deep notch 
or is prolonged intoa canal. This rule, however, is not 
without exceptions, 
- We will begin with Melampus lineatus Say, a small shell, 
not found on the open coast. It lives among the rank grass 
of the mudflats, where the water does not cover it ; 
for Melampus, unlike all of the other mollusks in this 
book, breathes air iustead of water. The shell is 
either plain or banded; and has fine white teeth 
Melampus within the aperture. 
The Scalide, Ladder shells, you will find on the beach. 
They have a long spire. The whorls are tubular, 
separated by deep sutures, and crossed by regular 
strong ribs. The aperture is oval. 
None of the species are common on our coast ; 
but the one most frequently met is Seala Hum- 
phreysii Kiener, a slender white species, having 
right rounded whorls. The riblets are rather 
widely separated, and upon each whorl there are 
Scala Hum. “ight or nine of them. 
phreysii. Scala angulata Say is a stouter, shorter shell, 
rarely found. 
Scala lineata Say has much more delicate riblets. 
It is brown, with a dark brown band near the base. 
Bittium alternatum Say is a small slender shell, 
Bittium from one-fourth to five-sixteenths of an inch in length. 
alterna The surface is cut into rounded beads by revolving and 
