176 THE CHICAGO ACADEMY OF SCIENCES. 



Limnaa columella COOPER, Proc. Cal. Acad. Sci., ii, V, p. 168, 1895. PILS- 

 BRY, Proc. Phil. Acad., p. 776, 1903. 



Limn & a macrostoma MARTENS, Biol. Cent. Amer., Moll., p. 379, 1899. 



"SHELL: Oblong-ovate, thin, irregularly striate, fawn-colored; 

 whorls four, moderately increasing, the upper ones very convex, the 

 last oblong, less convex ; aperture very slightly oblique, occupying two- 

 thirds of the whole length, narrowly oval, not very acute above; its 

 outer margin not much arcuated; basal margin rounded; columellar 

 margin almost vertically ascending, thin, triangularly reflexed above, 

 having a small umbilical slit in some specimens." (Martens.) 

 Length. Breadth. Aperture length. Breadth. 

 12.00 6.00 8.00 4.00 mill. (Martens). 



13.50 8.00 9.00 5.00 " 



16.00 8.00 10.00 6.00 " (Coll. Walker). 



TYPES : Location not ascertained. 



TYPE LOCALITY: Bigabo, South Panama. 



ANIMAL, JAW, RADULA AND GENITALIA : Unknown. 



RANGE: Central America and Mexico. Variety championi ap- 

 pears to be a race of the tropical life zone. It undoubtedly inhabits 

 a large part of Central America, but records are wanting, except from 

 two localities : 



MEXICO. 



TEPIC: Tepic (Cooper). 



MICHOACAN: Lake near Urupam (Rhoads; Pilsbry; Walker). 



MEXICO: Mexico (Von Martens; Dr. Berendt). 



CENTRAL AMERICA. 



NICARAGUA: Palvon (Walker). 



PANAMA: Bigabo, South Panama (Martens; Champion). 



GEOLOGICAL RANGE: Unknown. 



ECOLOGY : Not recorded. 



REMARKS: Championi is a form in which the spire is sharply 

 attenuated, the aperture is gracefully rounded as in typical columella 

 and the columella has the chalybea-like excavation, although Martens 

 describes the columellar margin as "almost vertically ascending," a 

 feature not shown in specimens from Central America or in the orig- 

 inal figure. It is not as compressed as casta and also lacks the obliquity 

 of that race. This race will undoubtedly prove to be a widely dis- 

 tributed form in Central America when that region is more thoroughly 

 explored. The Mexican references of Cooper and Rhoads seem to 

 be referable to this race. 



Pseudosuccinea francisca (Poey). Plate XXIV, figure 21. 



Limncea francisca POEY, Mem. Hist. Nat. Cuba, II, p. 32, 1858. PFR V Mai. 

 Blatt, V, p. 11, 1858. ARANGO, Rep. Fisico-Nat. Cuba, I, p. 137, 1865; II, p. 87, 

 1866. CROSSE, Journ. de Conch., XXXVIII, p. 260, 1890. 



