DISTRIBUTION OF BRACHIOPODS. 153 
having some molluscan features, such as a solid shell, though 
having nothing homologous with the foot, the shell-gland 
or odontophore of mollusks. 
In accordance with the fact that the Brachiopods are & 
generalized type of worms, the species have a high antiquity, 
and the type is remarkably persistent. The Lingula of our 
shores (LZ. pyramidata Stimpson, Fig. 104) lives buried -in 
the sand, where it forms tubes of sand around the peduncle, 
just below low- 
water mark from 
Chesapeake Bay, 
to Florida. It has 
remarkable vital- 
ity, not only with- 
standing the 
changes of tem- 
perature and ex- 
posure to death ¢ 
from various oth- Fig. 104 —Lingula pyramidata making sand-tubes, 
natural +ize.—After Morse. 
er causes, but will 
bear transportation to other countries in sea-water that has 
been unchanged. Living Lingule have been carried by Prof. 
Morse from Japan to Boston, “Mass. , the water in the small 
glass j jar contuining the specimens having been changed but 
twice in four months. The living species of. this cosmopol- 
itan genus differ but slightly from those occurring in the 
lowest fossiliferous strata. Between eighty and ninety liv- 
ing species are known, most of them living, except Lingula, 
which is tropical, in the temperate or arctic seas, while nearly 
2000 fossil species are known. The type attained its maxi- 
mum in the Silurian age, and in paleozoic times a few spe- 
cies, as Atrypa reticularis, extended through an entire system 
of rocks aad inhabited the seas of both hemispheres. 
Cuass V.—BRACHIOPODA. 
Shelled worms, with a limestone or partly chitinous, inequivalve, hinged” 
or unhinged shell, enclosing the worm-like animal ; with two sprrally coiled 
arms provided with ciliated cirri or tentacles, between which is the mouth. 
