74 THE NAUTILUS. 



orum Gray,' Desh., MS., in British Museum.]" The earlier syn- 

 onymy may be arranged thus: 1 



1823. Donax stultorum Mawe. The Linn. Syst. Conch., pp. 37, 

 40, pi. 9, f. 7 (no description; locality "Indian Seas"). 



1828. Donax stultorum Mawe, Gray. Index Testaceologicus, 

 Suppl., pi. 2, Donax, f. 2. Also Hanley's edit., 1856 (no descrip- 

 tion). 



1837. Cytherea ( Trigonella) crassatelloides Conrad. Journ. Acad. 

 Nat. Sci., Phila., vii. pt. 2, p. 253, pi. xix, fig. 17. 



1838. Trigona stultorum Gray. The Analyst, viii, p. 304 (no de- 

 scription; refers to " Venus stultorum Gray, Wood, Suppl., t. 2, f. 

 2." This is a false reference for Donax stultorum, loc. cit.). 



1843. Cytherea crassatelloides Con., Hanley. Descript. Catal. 

 Rec. Biv. Shells, p. 106. 



1843. Cytherea stultorum Gray, Hanley. Descript. Catal. Rec. 

 Biv. Shells, p. 106. (First description of stultorum. ) 



1844. Cytherea (Trigonella) crassatelloides Con., Hinds. Zob'l. 

 Voy. H. M. S. "Sulphur," Moll., p. 65, pi. 21, f. 1. 



1849. Trigonella crassatelloides Conrad, Journ. A. N. S., Phila., 

 i, pt. 3, p. 213. 



18 (?). Cythercea crassatelloides Con., Sowerby. The?. Conch., 

 ii, p. 612, pi. 127, f. 1-3. (G. stultorum placed in synonymy as the 

 young.) 



1853. Trigona crassatelloides Con., Desh., Catal. Conchif. Coll. 

 B. M., pt. 1, p. 46. 



1853. Trigona stultorum Gray, Deshayes. Catal. Conchif. Coll. 

 B. M. pt. 1, p. 46. 



1864. Cytherea crassatelloides Con., Reeve, Conch. Icon. Vol. 

 xiv, pi. 1, f. 3. 



1898. Cytherea (Tivela) crassatelloides Conrad. Stearns in Proc. 

 U. S. Nat. Museum, vol. xxi, pp. 371-378, plates xxiii-xxv. 



Conrad never actually used the combination " Pachydesma cras- 

 satelloides," though it is implied in his brief note of 1854. 



This species exhibits many varietal aspects, as is shown in the 

 paper last referred to. 



The generic synonymy is as follows : 



Trigonella Conrad, 1837. Journ. A. N. S., Phila., vii, pt. 2, p. 



1 Dr. Pilsbry has kindly assisted me in compiling the literary history of this 

 species. 



