258 Epwın CHAPIN STARKS, 
and bear ribs.. The parapophyses are attached to the centra by 
suture except the posterior three or four, which are anchylosed as 
usual. Posteriorly they grow longer and are turned downward. 
No boney bridge connects the opposite ones at the base. 
The ribs are articulated rather broadly to the parapophyses. 
No epipleurals are present. 
On the ventral surface of each abdominal vertebra is a large 
rather deep pit. Anteriorly these are on the median line, but a 
short distance posteriorly they are gradually deflected towards the 
left side until at the beginning of the anterior third of the ab- 
dominal cavity they are wholly to the left of the median line where 
a slight depression on the opposite side appears leaving a small 
median keel between. Posteriorly the pits gradually turn again to 
the median line until they are symmetrically in the middle again on 
the posterior abdominal vertebrae. 
Three specimens of Dallia were examined for this character 
and no variation was found. I know of no other form in which 
this peculiar unsymmetrical arrangement of these pits oceur. 
The hypural is a simple conical boss attached apparently by 
suture only to the three or four flattened rays which form the plate 
to support the caudal fin. Extending obliquely backward and upward 
is the usual ridge or urostyle, representing the upturned end of the 
pre-existing notochord. 
The flattened haemal and neural spines of five vertebrae 
anterior to the hypural assist in supporting the caudal fin and are 
attached to the vertebral centra by suture.') 
With the exception of three or four rays extending back 
from the hypural these rays are not in contact with each other 
to form a broad hypural plate. Anterior to these caudal fin 
vertebrae all of the haemal and neural spines are anchylosed to 
the centra. 
Large cartilaginous basal elements are present between the 
dorsal and anal rays and their respective interspinous bones. They 
fit into cup-shaped pits in the heads of the latter. 
Anterior to the dorsal many of the neural spines carry a supple- 
mentary interneural spine. 
1) Often the spines of only the last four vertebrae are attached to 
the centra by suture, or sometimes one spine only, or one side of one 
or both spines of the fifth are so attached. 
