Mr. G. B. Sowerby on Pentatrematites. 457 
Taz. Surry. XXXII, fig. 6. 
a. Small bones or arms in the Ambulacra. 
b. Ridges to which the bones a are affixed. 
c. The ridges removed, leaving a striated surface. 
PENTATREMATITES PENTANGULARIS. 
P. oblonga, superné latior, quinquangularis, ambulacris brevibus, angulis 
obtusis. 
Syn. Platycrinites pentangularis, Miller, (the arms being imaginary 
in his figure). 
Tas. Supru. XXXII, fig. 7. 
I regret that it is not in my power, owing to the length of time that has 
elapsed since the descriptions of former species were drawn up, to point 
out more in detail the distinguishing characters of these species ; I cannot 
however doubt that by careful attention to the plate and the characters 
above described, every difficulty will be removed. 
References to Tas. SuppL. XXXIII. 
Fig. 1. Pentatrematites angulata. Zool. Journ., vol. IV., p. 89. 
a. Lateral view. 
b. Base. 
2. Pentatrematites inflata, two views taken from different spe- 
cimens. Zool. Journ., vol. IV., p. 90. 
3.  Pentatrematites oblonga. Zool. Journ., vol. 1V., p. 90. 
4. Pentatrematites oblonga, var. 
5. Pentatrematites orbicularis. 
a. Lateral view. g 
b. Apex, 
6. Pentatrematites acuta, two views, 
7. Pentatrematites pentangularis. 
