142 BULLETIN 2 01, UNITED' STATES NATIONAL MUSEUM 



Cape Henry Light SW. by S. ■% S., lightship N. % W., 23 fathoms, 

 black mud and sand, December 4, 1920, 1 adult female, 7 mm., and 27 

 immature specimens. 



Distribution. — The above records extend the distribution of this 

 species from the coasts of New England to Louisiana. It is probably 

 distributed all along the coasts of the Atlantic shores of America in 

 shallow water. It appears to be found in association with M. munda, 

 at any rate in Chesapeake Bay and off Louisiana, and probably 

 everywhere where it occurs. 



Remarks. — This species may be recognized by the combination of 

 characters afforded by the unjointed antennal scale, the powerfully 

 developed endopod of the second thoracic limbs, and the form and 

 armature of the telson. It is very distinct from all the other species 

 of the genus from American waters. 



MYSIDOPSIS INERMIS Coifmann 



This species is diagnosed on page 245. 



MYSIDOPSIS CALIFORNICA Tattersall 



Figures 51, 52 

 Mysidopsis calif ornica Tattersall, 1932a, p. 307, figs. 14-25. 



Description. — Carapace produced in front into a very short, bluntly 

 rounded, triangular plate not covering any part of the eyestalks; 

 anterolateral angles rounded. 



Sixth segment of the pleon l 1 ^ times as long as the fifth. 



Antennular peduncle in the male shorter and stouter than in the 

 female, with the last joint relatively shorter and having a well devel- 

 oped setose lobe. Antennal scale (fig. 51, /) extending for one-third 

 of its length beyond the antennular peduncle, narrowly lanceolate in 

 shape and setose all around, nine times as long as broad, distal joint 

 equal to about one-quarter of the scale, apex rather acute; antennal 

 peduncle (fig. 51, /) about half as long as the scale and slightly 

 shorter than the antennular peduncle; third joint two-thirds of the 

 length of the second. 



Eyes large, about 1% as long as broad; cornea occupying nearly 

 half of the whole eye in dorsal view ; pigment black. 



Mandibles (fig. 51, a-c) with a molar process. Maxillulae (fig. 51, d) 

 with the inner lobe small and armed with two setae. Maxillae (fig. 

 51, e) with a well-developed exopod but with the setif erous expansion 

 from the second joint. 



Third to the eighth thoracic limbs (fig. 52, c) long and slender; 

 carpo-propodus divided by a transverse articulation into two sub- 

 joints; dactylus long and slender, longer than the distal subjoint of 



