46 THE NAUTILUS. 



Nephronaias dysom (Lea). Found with the above. They 

 were always more or less eroded, a good species. This stream 

 is some five miles west of Esmeralda and the above tw r o species 

 were the only ones found there. 



Potamopyrgus coronatus nicaraguanus (Ancey). Plentiful 

 in small bays or recesses of the river. 



Cochliopa dulcensis Marshall. Common with the other 

 small species taken with a net. 



Cochliopa izabal Pilsbry. Common. 



Neritina lineata reticulata C. & F. 



Neritina Usteri Pfr. Both these Neritina were scarce. 



Planorbis caloderma Pilsbry. A small species, little larger 

 than Segmentina obstructa, with more tumid whorls. 



Cyrenoidcs guatemalensis Pilsbry. One specimen. 



Mytilopsis sallei (Recluz). Numerous, on sticks and stones, 

 often in clusters of many individuals. 



JOCOLO. This plantation, on the north side of Lake Isabal, 

 is owned and operated by Mrs. Potts, a hospitable lady. The 

 commodious residence among palm and citrus trees is pic- 

 turesque viewed from the small wharf projecting into th" 

 lake. The lake is bordered by rushes, with here and ther 

 small open beaches of sand. On a point some distance above 

 the wharf was a windrow of fine drift, thrown up by a strong 

 wind; this was the only place where drift was found. It evi- 

 dently came down a river near by. This proved quite rich in 

 number of species, but specimens were scattering. The entire 

 windrow was worked over. The region has numerous small 

 streams with beds of rock, gravel and sand, with soft mud 

 where they enter the lake. 



Nephronaias guatemalanus (von Martens). A few speci- 

 mens referred to this were found in the lake with N. ravis- 

 tellus. It is some higher and lighter colored than that species. 



Nephronaias ravistellus (Morelet). Common. In 1914 they 

 were found mostly in water two to four feet deep, but in 1917 

 they were plentiful among the rushes and on the sandy beach 

 up to the water's edge. 



Nephronaias tabascoensis (Kuster). Mrs. Potts gave the writer 

 a few found by a native. 



