Zoology. 257 
University Circulars. He has studied five of the eight known 
West Indian forms, and finds that they vary considerably in habits 
ing almost impossible to separate the products of invagination 
into layers, or to separate others which wander from the ectoderm 
sions. _ He recognizes no less than twelve types, more than one 
of which may occur on a single fish. Most of these are small _ 
according as they are provided with (Opostomias micripnus, Echi- 
ores barbatum, Pachystomias microdon, Malacosteus indicus, 
stronesthes niger) or lack a pigmented mantle (Opostomias mieri- 
pnus). In no case are they provided with a reflector. The com- 
