PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 79 



Anodontite crcpue 



Anodoniite, shell oval, miuked with 

 radiating striae and with concentric 

 striae, which are elevated, rippled. 



Anodontites crispata 



Anodontites, testa ovali, striis longi- 

 tudinalibus transversisque elcvato- 

 crispa t is cancclla ta. 



Description: 



Height, 10 ligncs ; ' length, 1 pouce 7 lignes ; ° diameter, 6V2 lignes." 



Form, broad at the rear end, marked with a slight angle terminating at the 

 margin ; rounded at the front end. 



Valves, thin, furnished on tlieir surfaces with distant radiating grooves, less 

 marked near the margins and on the posterior area, crossed by concentric 

 striae which are more crowded, elevated, and waving and lightly lamellose 

 near the borders. 



Muscle scars, three in each valve; that of the posterior end large and super- 

 ficial, the two of anterior end unequal, rather deep. 



Beaks, eroded, rather prominent, situated anteriorly at the first quarter of the 

 length of the shell. 



Ligament, yellowish, extending from the beaks to the posterior third of the 

 shell. 



Color, brownish, corneous on the decorticated portion of the beaks, nacre 

 silvery and opaque near the margins. 

 This shell inhabits the rivers of Guiana whence it was sent to me by M. le 



Blond. 



EXPLANATION OF FIGURES d^ AND t' OF PLATE 8 



6. Anodontites crispata. Valves opened, natural size showing muscle scars, of 



which the lower two are united. 



7. The same shell closed, showing its convexity and its ligament. 



It may be noted that there is nothing in Brugiiiere's description 

 to differentiate between the genus Anodontites as we' now understand 

 it and other edentulous naiades, such as Anodonta Lamarck, Leila 

 Gra}^, Sfatha Lea, Mutela Scopoli, and others. Except for the spe- 

 cies cnspata^ described and figured along with the description of the 

 genus, and the locality from which that species came, the name Ano- 

 dontites might well stand for the genus Anodonta. Bruguiere did 

 not notice the peculiar triangular shape of the sinulus and appar- 

 ently saw no generic difference between his Anodontites crispata 

 and the common European edentulous naiades Anodonta cygnea Lin- 

 naeus {Mrjtihis cygneus L.), and A. anafina Linnaeus {M. anatina 

 L.), both of which he mentioned as belonging in his new genus. 



It seems remarkable that Bruguiere founded his genus on a shell 

 sent to him from a distance of 4,500 or moi-e miles when, right in 

 his own neighborhood, he had available Anodonta cygnea and others 

 that he thought belonged in his new genus. Had he used one of 



6 Professor Lamy, of the Paris Museum, has given me the following equivalents for these 

 measurements : 



Height, 10 lignes =22. 25 mm. 



Length, 1 pouce 7 lignes =42. 86 mm. 



Diameter, Oi/^ lignos =14. 66 mm. 



«PI. 1, fl;,'. 3, of tbis paper. 

 ' ri. 1, fig. 2, of this paper. 



