100 



BULLETIN 111, UNITED STATES NATIONAL MUSEUM. 



CADULUS (POLYSCHIDES) QUADRIDENTATUS ACOMPSUS, new subspecies. 



Plate 17, fig. 4. 



Several lots of shallow water Caduli from Puerto Barios, Livingston, 

 and Monkey River, Honduras, and from Belize Harbor, collected 

 by Schumo and now in the collection of the Philadelphia Academy of 

 Natural Sciences, are much smaller than are the shells of the typical 

 subspecies and possess besides a slight degree of lateral compression 

 in the extreme anterior portion of the shell. Most of the specimens 

 in these lots are banded by irregular rings of internal callous, but this 

 is not likely a diagnostic character. 



The type measures — length, 5.1 mm.; diameter, 75 mm.; anterior 

 aperture, 0.6 mm.; apical aperture, 0.4 mm. It is in the collection of 

 the Philadelphia Academy of Natural Sciences, Cat. No. 76557, from 

 Monkey River, British Honduras. 



The apical features are quite normal, though broken in most of the 

 examples before me. Some specimens are a trifle larger than the 

 type. This must not be confused with a small race of Cadulus quadri- 

 dentatus quadridentatus, already mentioned, from Barbados. 



It is a shallow-water form of the muddy bogs and probably ranges 

 along the entire Central American Altantic coast, but has not so far 

 been noted from the Antilles or the Florida region. In the museum 

 collection is one lot of five specimens. Cat. No. 314939, U.S.N.M., 

 collected by Schumo at Monkey River, British Honduras, and pre- 



