- LINGULA. -HIPPURITES. — 393 
Lineuna. Ly. p. 353, fig. 412.—The Brachiopoda re- 
_ ferred to this genus have a long peduncle, and their re- 
spiratory apparatus has no calcareous support; the recent 
species burrow in the sand, being usually inhabitants of 
shallow ‘waters. The ZLingule are readily distinguished 
from the Terebratulee by their imperforate, equivalved shells. 
One species is found in the Aymestry limestone, and several 
have been collected from the Mountain limestone, Oolite, 
_ and Shanklin sand. 
With reference to the species of Brachiopoda, particularly 
of the Terebratulee, which inhabit the depths of the ocean, 
| Professor Owen observes, that “both the respiration and 
_ nutrition of animals, which exist beneath a pressure of from 
_ sixty to ninety fathoms of sea-water, are subjects suggestive 
of interesting reflections, and lead us to contemplate with 
less surprise the great strength and complexity of some of 
_ the minutest parts of the frame of these diminutive crea- 
tures. In the unbroken stillness which pervades those 
_ abysses, the existence of these animals must depend on 
their power of exciting a perpetual current around them, in 
order to dissipate the water laden with their effete particles, 
and to bring within the reach of their prehensile organs the 
animalcules adapted for their sustenance.” 
t 
i 
_— = _——_ 
Hrepurites. This genus belongs to a group of fossil 
shells whose characters are somewhat problematical, some 
conchologists referring them to the ordinary bivalves, and 
others to the Brachiopoda. Although Hippurites have not 
been discovered in the British strata, I am induced to 
notice them in this place, in consequence of their great 
abundance in the Cretaceous deposits of the South of 
France, and in the Oolite of the Pyrenees; and also to 
illustrate the nature of a nearly related genus, Spherulites, 
of which one or more species occur in the Sussex Chalk. 
The Hippurite is of an elongated conical form, and fixed 
