1905.1 



NATURAL SCIENCES OF PHILADELPHIA, 



221 



Hondo river, two miles north of Hondo, Medina county, Texas (figs. 

 10-15), The shells are much smaller than in western Texas, usually 

 11 to 12 mm. long, and the diameter is generally less than 4 mm. A 

 large proportion of the shells have "overhanging" upper whorls. 

 They were picked out of river-debris, and probably came from the hill 

 country some miles farther north. The measurements of fifty adult 

 shells, all the perfect ones I found, follow: 



The lengths give the following curve, which, although of no great 

 value on account of the small number of variates, is given for what it 

 is worth. 



8.5 '"'"• 



J ^3,7) 1/22/6/0 2/ //4-/ii/ •/jr/afej. 



Genus MICROCERAMUS Pils. and Van. 



Nautilus, XI, p. 107; Proc. Acad. Nat. Sci. Phila., 1898, p. 281; Manual of 

 Conchology, XVI, p. 151. 



