THE NAUTILUS. 81 



Unio charruana d'Orb. Lake Potrero, near Mnldonado, Uru- 

 guay. 



Unio I'ai'iabilis Maton. Uruguay River at Fray Bentos. 



Unio perceformis Lea. Rio de la Plata at Colonia. The rug;e on 

 the posterior slope mentioned by Lea as perhaps inconstant, are 

 present in the specimens collected. 



MUTELIIXE. 



Monocondylcea Pazii Lea. Colonia, Uruguay. 



Monocondylcea lentiformis Lea. Colonia, Uruguay. 



6 la bar is sirioiies d'Orb. Rio San Carlos, Uruguay. 



Glabaris latomarginatus Lea var. fvlix Pils. Colonia, Uruguay. 



Glabaris riibiciinda Lea. La Plata River at Colonia, Uruguay ; 

 Uruguay River, Paysandu. 



Glabaris li/cidus d'Orb. La Plata River at Colonia, Uruguay. 



Glabaris trupesialis var. eygneiformis Pils. Pond and a small 

 creek near Maldonado. 



Glabaris trapesialis var. exotiais Lain. 

 Anodonta exotica Lam. An.s. Vert., vi, 1819, p. 87; Deleasert, 



Rec. de Coq., pi. 13, f. 1 (figure of type). 



Anodon scriptus " Fer." Sowb., Conch. Icon., pi. 4, f. 9 (1867). 



It is narrower than G. trapesialis, long, the anterior end very nar- 

 row, angled at end of hinge-line; posterior muscle-scar quite near 

 the sinus at edge of hinge ligament, connected therewith by a short 

 impression. 



Rio San Carlos, Uruguay. Rather small specimens, but agreeing 

 with the figure of type in Delessert's Recueil. 



Glabaris Forbesianns Lea. Rio de la Plata, Colonia, Uruguay. 

 Lea's figure was from a deformed shell, and the specimens would 

 hardly have been recognized as Forbesiama had it not been for the 

 kindness of Mr. Simpson, who compared with the types. 



ISAAC LEA DEPARTMENT 



[Conducted in the interest of the Isaac Lea Conchological Chapter of the Agassi/. Associa- 

 tion by its General Secretary, Mrs. M. Burton Williamson.] 



Members of our Chapter will please bear in mind the fact that 

 the annual reports are due in December. We anticipate some fine 

 papers this year as our members have been enthusiastic in their 

 study of shells. 



