THE FAMILY OF NAIADES. 



Unto. Lam., 

 Cunicula. Swain., 

 Ligumia. Swain., 

 Theliderma. Swain., 

 Megadomus. Swain., 

 JEglia. Swain., 

 Naida. Swain., 

 Canihyria. Swain., 

 Mysca. Turton, 

 Potomida. Swain., 

 Lymnadea. Swain., 

 Iridea. Swain., 

 Castalia. Lam., 

 Na'ia. Swain., 

 Hyria. Lam., 

 Hyridella. Swain., 

 Iridina. Lam., 

 OalUseapha. Swain., 

 Mycetopus. D'Orb., 

 Lamproscapha. Swain., 

 Symphynota. Lea, 

 Anodon. Lam., 

 Hemiodon. Swain., 

 Patularia. Swain., 

 Calceola. Swain., 

 Alasmodon. Say, 

 Uniopsis. Swain., 

 Margaritana. Schum., 

 Complanaria. Swain., 



represented by Unio sulcatus. Lea. 



" " Unio rubiginosus. Lea. 



" Unio rectus. Lam. 



" " Unio lacrymosus. Lea. 



" " M. gigas. Swain. 



" " Unio ovatus. Say. 



" " Unio ater. Lea. 



" " Unio spinosus. Lea. 



" " Unio pictorum. Lam. 



" '' Unio sinuatus. Lam. 



" " Unio alatus. Say. 



" " Unio granosus. Lam. 



" " Castalia ambigua. Lam. 



" " Unio corrugatus. Lam. 



" " Syria syrmatophora. Lam. 



" " Unio australis. Lam. 



" " Iridina exotica. Lam. 



" " Iridina Nilotica. Sow. 



" " Mycet. soleniformis. D'Orb. 



' " Anodonta siliquosa. Spix. 



' " Unio Isevissimus. Lea. 



' " An. cygnea. Lam. 



' " An. areolatus. Swain. 



' " An. rotundus. Spix. 



: " Unio calceolus. Lea. 



; " Alas, undulata. Say. 



: '' U. mytiloides. Raf. ? 



; " M. margaritifera. Lin. 



; " Alas, rugosa. Barnes. 



Retzius, Nova Testaceorum General 1788, established the genus Unio, of which he 

 makes two divisions, viz. : — 



* Without lamellar teeth — 



1. Unio margaritiferus. 



represented by Mya margaritifera. Lin. 



** With lamellar teeth — 





2. Unio crassus. 



" " Unio crassissimus. Fer. 



3. Unio tumidus. 



" " Unio ovalis, of British Zoologists. 



4. Unio pictorum. 



" " Unio pictorum. Lin. 



5. Unio ovalis. 



" " Unio tumidus. Retz. 



6. Unio corrugatus. 



" " Unio corrugatus. Lam. 



1 I have never been able to examine this rare work until recently, it being now in the Library of the Academy 

 of Natural Sciences. The establishment of the genus Unio has been usually given, by French authors, to Bruguiere, 

 but the English and German writers give it to Retzius so universally, that I have followed them. But now, on a 

 careful examination of the work itself, it seems to me that the genus belongs to L. M. Philipsson, the author of the 

 Dissertation, Retzius himself being the presiding officer of the institution where this thesis was presented. 



