160 AMERICAN JOURNAL 



The method I have employed to collect the shell of this and 

 other species, which are too minute to be taken by a scoop, is by 

 pulling up by the roots the submerged plants, and washing them 

 in a large bottle of water. The finer mu<l being removed by 

 agitation of the water, the shells were searched for in the coarser 

 sediment. 



S. meridionale is very active, and climbs the sides of a vessel 

 with great facility. 



43. Cyrena solida, Phil. 



With Neritina virginea in brackish water pools, Greytown, 

 burrowing to a depth of one or two inches in the sandy bottom. 

 Recorded from Belize. 



44. Unio Rowelli, Lea. 



Rivers Malacatoya and Estar, Nicaragua. Chagres river,* 

 New Grenada (Lea). 



45. Unio Gabbiana, Lea. 

 North shore of Lake Nicaragua. 



46. Unio 



North shore of Lake Nicaragua. 



47. Unio 



River Tipitapa (or Panaloya). 



48. Anodonta Bridgesii, Lea. 



River Tipitapa, and sand-bar north of river Estar, Lake 

 Nicaragua. 



The largest specimen collected measures four and a half inches 

 in length. 



49. Anodonta in^equalis. Lea. 



Lake Nicaragua, near San Ubaldo, and River Malacatoya. 



50. Anodonta luteola, Lea. 



River at Tierra Blanca and River Malacatoya. 



51. Mycetopus Weddelli, Hupe. 



The genus Mycetopus, hitherto limited in the western hemi- 

 sphere to tropical South America, is represented in Nicaragua 

 by one species, the identity of which with the Brazilian form is 

 somewhat doubtful in the absence of specimens for comparison. 

 The Central American analogue appears to present differences 



