1905.1 NATURAL SCIENCES OF PHILADELPHIA. 



345 



SENILITY AMONG GASTROPODS 



by burnett smith. 



Introduction. 

 The critical study of the development of Gastropod shell ornamen- 

 tation has, until recent years, attracted the attention of few scientists 

 in the United States. In Europe as early as 1889 Koken^ made a 

 carefia study of Paleeozoic Gastropods. This was followed m 1896 

 by the Countess von Linden's^ study of the ornamentation and color 

 patterns in Voluta, Strombus and Coyius. In the United States, the 

 first use of gastropod shell characters in the study of phylogeny occurs 

 in the short notes of Heilprin' in 1888, dealing with the phylogeny of 

 Fulgur perversum and Strombus leidyi; and of Ueidy* and Wilcox on 

 the ancestry of Fulgur -perversum. 



In 1900, A. W. Grabau presented a thesis at Harvard University 

 dealing with the phylogeny of Fusus and allied forms. In June, 1902, 

 the writer^ applied the methods of the Countess von Linden to a study 

 of the Fulgurs, and later in the same year A. W. Grabau« published a 

 paper dealing with the general features of gastropod shell development. 

 In 1903 Prof. Grabau^ discussed the phylogenetic relations of the Ful- 

 gurs, and in the following year published an elaborate phylogenetic 

 study of Fusus? 



In most of the above papers there is an attempt made to compare 

 ontogeny with palfEontogeny, dealing, therefore, with both recent and 

 fossil forms. The individuals of species are studied from the earliest 



1 Koken E "Ueber die Entwicklung der Gastropoden vom Cambrium bis 

 zur Trias '' jdhrh. Mineral., 1889, Beilage, Band VI, pp. 305-484. 



'Linden, Graf en M. von,' "Die' Entwicklung der Skulptur und der Zeichnung 

 bei den Gehausschnecken des Meeres," Zeit. Wiss. Zool., LXl, pp. Zbl-6U. 



3 Heilprin, A., "The Geological Evidences of Evolution 



^ Leidy, J., "Remarks on the Nature of Organic Species," Tr. Wag.-Inst. PInla., 



^''^'Imlth' Burnett, "Phylogeny of the Species of Fulgur with remarks on an 

 abno^al'sp^cimen of pilgur canaliculatum and sexual dimorphism in Fulgur 

 carica," Proc. Acad. Nat. Sci. Phila., June, 1902. ^^ ^ ,. , „„ ^ „... 



«Gribau A W "Studies of Gastropoda," A?n. ATai., Vol. 3b, p. 9^6. 



'Grabau, A. wl, "Studies of Gastropoda, II-Fulgur and Sycotypus," Am. 



'^"^ Grlbau^V W^^""phylogeny of Fusus and Its Allies," Smithsonian Miscel- 

 laneouTcollectionsy.rt of Vol. XLIV (No. 1,417), Washington, 1904. 



