140 BULLETIN 201, UNITED' STATES NATIONAL MUSEUM 



First thoracic limbs (fig. 50, e) of the normal form characteristic 

 of the genus with the second and third joints of the endopod fused; 

 the limbs are shorter and stouter than in European species of the 

 genus especially with regard to the sixth joint; seventh joint not 

 longer than broad ; dactylus stout and straight. 



Figure 50. — Mysidopsis bigelowi Tattersall: a, Anterior end, dorsal view, X 22; b, antennal 

 scale and peduncle, X 43}<i; c, maxillula, X 43J4; d, maxilla, X 43}<$; e, endopod of first 

 thoracic limb, X 43^;/, endopod of second thoracic limb, X 43}£; g, endopod of third 

 thoracic limb, X 43 }i; h, telson, X 66%. 



Second thoracic limbs (fig. 50, /) with the endopod relatively 

 enormously developed, much more robust than in any known species 

 of the genus and as far as the present material goes, more robust in 

 the female than in the male; this relative development of the limbs 



