488 MOLLUSCA. 
terminal ends truncate obliquely, and a little concavely backwards, 
having a lateral laciniation near the anterior angles, and a longitudinal 
one in the posterior margin near the angle: the body of the animal is 
somewhat roseate, with a central dusky spot. Posterior cornua of 
the shell long, corpulent at base, somewhat tortuous, and running to 
a prolonged point. 
Expansion of alar appendages an inch and a half; whole length of 
the shell and animal the same. 
Obtained in the equatorial Atlantic. 
Described from a figure by Dana. It is remarkable for its long and 
corpulent appendages. 
Figure 603, animal as in life, with the shell. 
CiLEopora Exacuta (Gould). 
T. pellucida, triangularis, subtus concava, supra per convexa antice, 
rotundata, posticé valde acuminata, lateribus concaviter arcuatis. 
Animal cervice longo et alis divergentibus oblongo-ovalibus instructus. 
Alar expansions arcuate, rounded at extremity, the posterior edge 
loosely undulate; the basal lappet large and triangular; the conical 
papille at the mouth are dark, as well as the central abdominal mass; 
otherwise colourless. 
The sHELL is an equilateral, spherical triangle, the base convexly 
rounded, and the sides concavely excavated, producing thus a long, 
acute caudal point: the under valve is slightly concave, and the upper 
valve very convexly arched: in front is a small opening, through 
which the neck of the animal passes. 
Length about half an inch; greatest breadth equal to about two- 
thirds the length. 
Found by Mr. Dana, in latitude 44° N., long. 154° W., that is, about 
30° west of the mouth of Columbia River. 

