214 BRACHYOPODS. 



Xylotria Stutchburryi, Jeff., Stuch-bur'-ry-i, has a 

 very small shell, and is found in southern waters. 

 The valves are white and triangular, and the pens are 

 minute and club-shaped. 



The Brachyopods are usually classed with the mol- 

 lusks, though they have certain characteristics which 

 ally them to the worms. In structure they are quite 

 unlike the Lamellibranchs, but they resemble them 

 in appearance, for they have bivalve shells. These 

 shells, however, instead of being upon the right and 

 left sides of the animal, cover the upper and under 

 surfaces. The beak of the upper valve projects over 

 the lower, and in this projection is a hole, through 

 which passes the fleshy stalk that anchors the animal 

 to its resting place. 



Within the shell are two long, feathery arms, 

 which may be extended and used for catching food. 

 They serve also as gills; at least they partly perforin 

 that office. These curious arms were once considered 

 analogous to feet, hence the name, Brachiopod, or 

 Arm-footed. 



Most of the Brachiopods had been dead for ages 

 before the creation of man, and their fossil remains 

 are very abundant in the earlier rocks. But there are 

 a few living species, though specimens are rarely 

 obtained, and most of them live in quiet deep water. 



Terebratula unguiculus, Cpr., Ter-e-brat'-u-la un- 

 guic'-u-lus, has a wrinkled, gray shell, usually less 

 than an inch in length. I have seen a northern spec- 

 imen attached to the shell of a dead gasteropod. 



Waldheimia fiulvinata, Gld., Wald-hi'-mi-a pul-vi- 

 na'-ta, from the north and W. Californica, from the 

 state indicated by its name, have smooth, thin, sub- 

 globular shells, of an ashy color and a larger size. 



