APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 205 



The following account of the Copepoda was prepared by 

 Professor Chauncy Juday, of the University of Wisconsin. 



In the Plankton collection, from Lakes Atitlan and Amatitlan, 

 the Copepoda are represented by only two forms. 



Family Centropagidae. 



Diaptomus albuquerquensis Herrick. 



Four specimens of this species were found in the material 

 from Lake Atitlan, and four in that from Lake Amatitlan. Length 

 1.4 to 1.7 mm. This form has been reported from Colorado, 

 New Mexico, and the City of Mexico. 



Family Cyclopidre. 



Cyclops oithnoides Sars. 



A few adults were found in the collection from Lake Atitlan. 

 Length o . 5 mm. A considerable number of immature specimens, 

 which probably belong to this species, was found in the collec- 

 tions from both lakes. 



SHELLS OF LAKE AMATITLAN. 



With the exception of one species, Sph&romelania largillierti, 

 shells are not abundant about the shores of the lake. No bivalves 

 were taken, and probably none exists there. My stay at Lake 

 Atitlan was short, and no shells were collected there. The few 

 unsuccessful searches made for these indicate that shells are not 

 abundant on the shores of this lake. 



For the identification of these shells I am indebted to Dr. 

 Ball and to Dr. Bartsch, of the Smithsonian Institution. 



Family llelanideB. 



Sphieromelania largillierti Phil. 



This is the largest and by far the most abundant species of 

 shell found in the lake. It is found everywhere along the shore 



