218 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 115 



Antennule of early encysted forms one-segmented, attached to 

 anterior ventral surface in frontal region. Single segment irregular 

 in shape, flaccid, tapered to round tip bearing six small, plumose setae. 

 Middle of antennule with irregular row of six setae, each with several 

 setules. Two segments of late encysted antennule visible inside early 

 encysted antennule (figs. 20e,f). 



Antennule of late encysted and recently excysted forms two- 

 segmented. First segment two and a half times length of second in 

 late encysted specmiens, approxunately two times length of second 

 segment in recently excysted specimen. Lateral margins almost 

 parallel in proximal region, with knoblike convexity of anterior sur- 

 face in distal region. First segment with eight short, plumose setae, 

 one long plumose seta, two large and two small lobate protrusions, 

 all from knoblike convexity (fig. 20h). 



Second segment of excysted specimen slightly longer than that of 

 encysted, both with two plmnose setae on distal portion of posterior 

 margin, three plumose setae from posterior distal smiace, and six 

 naked setae from anterior distal surface. Setae and lobes on 

 excysted specimen developed to slightly greater extent than on 

 encysted specimens (figs. 20g,h). 



Second antenna of early encysted specmiens two-segmented, 

 attached just posterior to base of antennule. Second antenna con- 

 sisting of large, conical first segment and small, irregular second 

 segment. First segment of older specimen more slender than that of 

 younger, with indication of segmentation visible inside appendage but 

 not externally; both older and younger specimens with small, tubercu- 

 lar projection from posterior distal surface. Distal segment of older 

 specimen recurved more than that of younger; younger specimen with 

 minute, lobate projection from inner distal surface of segment; older 

 specimen without lobate projection but with minute, irregular exten- 

 sion of distal surface (figs. 20i,j). 



Second antenna of older encysted and recently excysted specimens 

 three-segmented, attached slightly posterior and medial to antennule 

 base. First segment short, broad, width and length about equal, 

 lateral margins irregular, with well-developed articular surface on 

 outer proximal edge articulating with concave depression of segment- 

 like extension of ventral surface of cephalothorax. Inner distal surface 

 of first segment projecting beyond remaining distal surface as broad 

 articular surface, fitting in heavily chitinized depression on outer 

 proximal surface of second segment. Second segment strongly devel- 

 oped, slightly longer than wide, longer than first segment; lateral 

 margins somewhat irregular, inner margin convex. Inner distal sur- 

 face of second segment projecting as rodlike structure, articulating 

 with knobhke process on third segment. Third segment and terminal 



