No. 407.] PECTEN IRRADIANS LAMARCK. 877 
self-adjustments to accidents or as sports which represent 
typical conditions in allied species. 
LITERATURE CITED. 
'98 DALL, W. H. Tertiary Fauna of Florida. Trans. Wagner Free 
Institute of Science, Philadelphia. Vol. iii, Pt. iv, pp. 571-947, 
Pls. XXIII-XXXV. April, 1898. 
'99 DuNCKER, G. Variation Statistics in Zodlogy. Natural Science. 
Vol. xv, pp. 325-337. November, 1899. 
'90 JacksoN, R. T. Phylogeny of the Pelecypoda. Mem. Bost. Soc. 
Nat. Hist. Vol. iv, pp. 277-400, Pls. XXIII-XXX. July, 1890. 
'99 VERRILL, A. E. A Study of the Family Pectinide, with a Revision 
of the Genera and Subgenera. Trans. Conn. Acad. Arts and 
Sciences. Vol. x, pp. 41-95, Pls. XVI-XXI. 
