: 302 C. D. Walcott—Injury to a Trilobite at time of Moulting. 
Cambridae, Aug., 18 
Arr. XXXUL.—Jnjury sustained by the Eye of a Trilobite at the 
_ time of the Moulting of the Shell; by CHARLES D. Watcorr. 
oe ILLI1AM P. Rust, of Trenton Falls, N. Y., called my 
re attention some time since to the eyes of a small but very perfect 
ee imen of Jilenus crassicauda, from the Trenton limestone, 
s “that he bas in his beautiful collection of Trenton fossils. 
hig oe ohed ener via out while he pi aera. oe This 
is shown by the peculiar growth of the shell about the aperture 
formerly occupied by the visual surface of the eye. The mar- 
gins are turned in, rounded and Seniresier and the size of the 
sbral lobe materially lessened. An injury to the visual 
eo surface would scarcely produce this effect if the shell was hard. 
Tf slightly injured before the moulting of the shell, the separa- ce 
tion would be imperfect and the visual surface carried away ees , 
the old shell would leave a cavity around whieh the new shell 
_ would form as in the eye before us. _if injured befor’ the new 
- shell had hardened, that effect might b the prob- 
mi + eho 
abilities are that the loss of the visual. surface niacin me 
_ Among the thousands of louie that have passed sheoust 
_ my hands in which the eyes were preserv ed, I have never no- 
_ticed any distortion or injury that occurred during the life of 
the oe In a few instances, the. shell of the pyentian, of 
- Y nee of | eture that — : 
appears fo to ‘have occurred bie the life of she. sateen but 
h very unsatisfactory. To Mr. Rust’s skill in work- 
2S bed and also in detecting the char- 
indebted for some eS 
vulting of 
