6 PROCEEDINGS OF THE NATIONAL. MUSEUM. vol.65 



cover the carapace with a confluent net of black lines when ex- 

 panded. The eyes are strikingly large and well formed. 



Cephalic appendages. — The antennules (fig. 3), mandibles (fig. 

 5), maxillules (fig. 6), and maxillae (fig. 7) have the typical brach- 

 yuran structure. The antenntie (fig. 4) are as long as the rostral 

 spine. They appear as stout spikes carrying very inconspicuous ex- 

 opodites. The distal portion of the spike is covered with minute 

 hairs. The exopodite appears as a tubercle carrying a single hair. 



Thoracic appendages. — The first and second maxillipeds (figs. 8 

 and 9) have the usual structure, with four swimming hairs. They 

 are both very large for such a small zoea. The endopodite of the 

 second maxilliped has three segments. 



Abdomen. — The joints of the abdomen are unusually well formed. 

 There are pronounced lateral tubercles on segments 2, 3, and 4 (fig. 

 10). The telson is typically bicornuate. 



Genus SESARMA Say. 



The zoeas of the two species of Sesarma here described are so 

 similar morphologically that they can be distinguished by their 

 pigmentation only and by a slight difference in size. That of S. 

 reticulata (Say) (figs. 13 and 14) is smaller and somewhat more 

 heavily pigmented. It is most readily distinguished by the presence 

 of a pigment spot behind the dorsal spine and the absence of pig- 

 ment on the first maxilliped. The zoea is 1.3 mm. long and .4 mm, 

 dorsc-ventrally through the cephalothorax. 



The first zoea of S. cinerea (Bosc) is noticeably robust and its 

 olive-green eyes are conspicuous objects. Its length is 1.6 mm. and 

 its carapace depth 0.6 mm. It is best distinguished by the pigmenta- 

 tion of both maxillipeds. 



FIRST ZOE.\ OF SESARMA. 



Cephalothorax. — The dorsal and rostral spines are relatively 

 slender and short and the dorsal curves pronouncedly posteriorly. 

 The eyes are perhaps a little smaller than they are usually. 



Cephalic appendages. — Only the antennae are not typically 

 brachyuran. They show a well-developed exopodite (fig. 16). The 

 exopodite is a cylindrical segment about one-third as long as the 

 spine. It bears two or three hairs. 



TJhoradc appendages. — These do not show any unusual feature. 



Abdomen. — The lateral border of each segment is produced some- 

 what posteriorly as a deltoid tooth. The telson is typically bicorn- 

 uate. 



