630 MEMOIRS OF THE CARNEGIE MUSEUM. 



The greatly elongated shape and the jjosterior retractor-scar are evidently 

 correlated characters. This subgenus apparently stands close to the crispata- 

 grouj) of Anodontites in the sculpture of the epidermis. 



Swainson introduced Lamproscapha for four species, of which the first {elongata 

 Swainson) was doubtfully referred here. The second is ensiformis. If the latter 

 is to be separated from Anodontites, Lamproscapha is the oldest available name. 



65. Anodontites (Lamproscapha) ensiformis (Spix) (1827). 



Anodon ensiformis Spix & Wagner, 1827, p. 31, PL 24, figs. 1, 2. Sowerby, XVII, 



1867, PI. 11, fig. 31 (young). 

 Anodonta ensiformis D'Orbigny, 1843, p. 618, PL 79, fig. 10. Von Ihering, 1890, 



p. 161. 

 Glaharis ensiformis Simpson, 1900, p. 932. 

 Anodontites ensiformis Simpson, 1914, p. 1455. Haas, 1916, pp. 36, 57. 



Type-locality not given. 



Other Localities. — Rio San Miguel (= Rio Itonama), Bolivia (tributary to 

 Guapore) (D'Orbigny); Rio Piray, Santa (Vuz de la Sierra, Bolivia (tributary to 

 Rio Marmore, into which the Guapore flows) (D'Orbigny); Rio Napo, Mazan, ' 



Peru (Haas). Repeatedly reported from Brazil, but no e.xact localities given. ^' 



Lea (Obs. XIII, 1874, p. 27) mentions this species as having been found in 

 Guyana, in connection with a species from Yuruari River (tributary to Essequibo). -^^ A 

 Simpson (1900, p. 932 and 1914, p. 1456) describes a new species {A. fcdsa) taken 5 / i;nll 

 by Lea for ensiformis, from the same river (Yuruari), "a branch of the Orinoco." ^^ 



The Yuruari, however, is a tributary of the Essecjuibo, but is located chiefly in 

 Venezuela, not in Guyana, and does not belong to the Orinoco-system. 



Neio Locality. — Rio Machupo, San Joaquim, Bolivia (tributary to Rio Itonama 

 and Guapore) (J. D. Haseman coll., September 5, 1909). Four specimens, three 

 of them with soft parts. Another specimen is in the Carnegie Museum (from the 

 Hartman collection) labeled "Brazil." 



Distribution. — Definite localities are so far known only from the upper Amazon 

 and Madeira drainages in Peru and Bolivia. 



Characters of the Shell. — Shell moderately thick; outline much elongated, 

 knife-like, pointed behind. Height 25 to 33 pr. ct. of the length. Valves not 

 gaping. Dorsal and ventral margins practically parallel, except towards the 

 posterior end, where the dorsal margin curves in a gentle curve or a very obtuse 

 angle into the posterior margin, which descends obliquely and is straight or gently 

 concave. At the posterior end the margin curves sharply around to the ventral 



