A REVIEW OF THE MYSIDACEA 147 



to the maxilla: M. didelphys (Norman), M. gibbosa G. O. Sars, M. 

 angusta G. O. Sars, M. bigelowi Tattersall, M. acuta Hansen, M. 

 inermis Coifmann, M. calif ornica Tattersall, M. major (Zimmer), M. 

 similis (Zimmer) , and M. schnitzel (Zimmer). The form of the 

 maxilla in M. indica Tattersall, and M. kempii Tattersall is not known, 

 but in all probability in both species an exopod is present. 



Other characters which are common to the three species of this new 

 genus and may prove of generic significance, are: (1) The narrowly 

 lanceolate form of the antennal scale; (2) the fact that the spines 

 arming the lateral margins of the telson are confined to the distal por- 

 tion only, the proximal part of the margins being smooth. 



METAMYSIDOPSIS MUNDA (Zimmer) 

 FlGUBE 54 



Mysidopsis munda Zimmer, 1918, p. 17, figs. 8-15. 



Description. — General form of the body slender ; carapace somewhat 

 produced in the middorsal line into a broadly rounded rostral plate. 



Eyes large, cylindrical, extending forward beyond the distal end of 

 the second joint of the antennular peduncle, cornea shorter than the 

 eyestalk. 



Antennular peduncle rather long and slender, first joint longer than 

 the third. 



Antennal scale (fig. 54, a) about as long as the antennular peduncle, 

 rather narrowly lanceolate, outer margin somewhat concave, 5 to 6 

 times as long as broad, distal joint marked off by a distinct suture. 



Antennal peduncle (fig. 54, a) extending forward as far as the suture 

 of the scale. 



Maxilla (fig. 54, c) without exopod and without the setiferous ex- 

 pansion of the lobe from the second joint. 



Carpopropodus of the endopods (fig. 54, /) of the third to the eighth 

 thoracic limbs divided into two sub joints by a transverse suture. 



Telson (fig. 54, i) broadly triangular, one and a third times as long 

 as broad at the base, proximal two-thirds of the lateral margins smooth 

 and without spines, distal third of the lateral margins armed with 

 about 18 short acute spines, the terminal pair at the apex somewhat 

 longer than those on either side of them ; apex entire, without cleft. 



Inner uropod (fig. 54, h) one and a half times as long as the telson 

 with a row of about 46 spines extending from the statocyst almost to 

 the distal end of the lower inner margin. 



Outer uropod twice as long as the telson. 



Length of adults of both sexes 6 mm. 



Occurrence. — Gulf of Mexico : Calcasieu Pass., La., W. H. Spauld- 

 ing, collector, No. 19, 7 : 30 p. m., September 19, 1907, 4 males. East 

 coast of United States : Fort Macon, Beaufort, N. O, August 2, 1915. 



