52 



ANODONTA. 



OBOVATE. 

 *Spixii. 



jyorh. 



porcifer. 1 Gray. 



*trapezialis. Lam. Slain. Pot. 



Kiist. 

 An. exotica? Lam. Guv? D' Orb. 



Desk. 

 An. giganteus. Spix. Menke. 



Kiist. 

 An. pencillatus? Gray. 

 An. Susannse. Gray. 

 An. radiatus. Spix. 

 An. trapezia. Kiist. 



*anserina. Spix. 



$ 





H 





K 





O 





P 





o 





fc 





< 





H 



ts 



H 





O H 





S5 





r» 

























(X 





oa 





K 





O 





z 







. , 



OBOVATE. 



Georginfe. 4 Gray. 



Parishii. 5 Gray. 

 Leila Parishii. Gray. 



*Blainvilliana. 6 Lea. 



An. trapezialis. Crouch. 

 Irid. trapezialis. 1 P' Orb. 



*esula. 8 Jan. 



Irid. esula. 9 P' Orb. 

 Leila esula. 10 Gray. 



crassa. Swain. 



*angulata." Lea. 



1 Never having seen this species, I place it here on Mr. Gray's authority. 



2 So far as ,1 have been enabled to examine specimens of this and trapezialis, I am disposed to think they are 

 not distinct species. 



3 The figure, PL 90, given in the edition of Cuvier by his pupils, is said to be reduced to one-half. It seems to 

 me to be a good representation of An. lato-marginata (nobis), and not like Lamarck's exotica. 



4 I have not seen this shell. It seems to be nearly allied to Blainvilliana (nobis), judging from the figure in 

 Griffith's Cuvier, PL 19, Fig. 3. It is from Paraguay. 



5 Fide Mr. Gray. 



6 In my description of Blainvilliana (Observations on the Genus Unio, vol. i. p. 189), I observed that I was 

 induced to believe that the animal of this shell would be found to differ from that of the genus Anodonta. M. 

 D'Orbigny, in his Synopsis of the Fresh Water Shells of South America, has in fact so found it. The animal has 

 two tubes. Nevertheless, although I then proposed, if such should be the case, that it should be placed in a new 

 genus, under the name of Columba, I have continued it in the subgenus Anodonta, as, with the present artificial 

 system, which is founded on the hinge, it could not with propriety be elsewhere classed. When the family shall 

 be arranged in a system founded on the animal structure only, it evidently must be changed, and I doubt then if 

 it should be placed in the genus Iridina, for, although it is likely that all the species of that genus have two 

 tubes, they do not seem to possess the deflected palleal cicatrix, which I noted in the description of Blainvilliana. 



7 M. D'Orbigny, at p. 43, Synopsis Ter. and Fluv. Mollusque, makes An. trapezialis, Lam., a synonym to 

 his Iridina trapezialis; but I think that Lamarck's An. trapezialis is a different shell. I cannot but think that 

 D'Orbigny 's I. trapezialis is my An. Blainvilliana. 



8 M. D'Orbigny thinks that this is my Blainvilliana, but, having his specimens and mine of both these species, 

 I am induced still to believe that I am correct. The two specimens resemble each other, but are certainly distinct. 

 The deflected palleal cicatrix exists in both, but the esida is more rotund, and the dorsal margin is more sinuous, 

 the nacre being bluish white, while the five or six specimens of Blainvilliana which I have seen are all salmon color. 

 The esula would come under my proposed genus Columba (note 6 above), if the animal differs, as I suppose it does, 

 from Anodonta. 



» Mag. de Zool, 1835. 



10 Gray's Genera. 



11 This very curious and interesting species was described from a single imperfect valve, brought by Mr. Nut- 

 tall from Oregon. Some years afterwards, Lady Catherine Douglas recognized it among the shells sent by Sir 



