HAWAnAN ACANTHURID CALIGOIDS — LEWIS 219 



process falciform, more so in excysted than in encysted specimens. 

 Length of third segment and terminal process slightly shorter than 

 combined lengths of first two segments. Third segment with two 

 spinelike accessory processes on inner surface, one on proximal, sec- 

 ond on distal portions of segment. Division between terminal process 

 and segment distinct (fig. 20k) . 



Mandible of early encysted, late encysted and recently excysted 

 specimens four-parted. Mandible of late encysted and recently 

 excysted specimens slightly longer than that of early encysted. First 

 part of mandible of all specimens broader proximally than distally, 

 with even taper to junction of second part. Second part short, 

 slightly more than half length of first part in early encysted specimens, 

 less than half in late encysted and recently excysted specimens; with 

 little taper to junction of thu'd part. Third part elongate, almost 

 twice length of first part, tapered slightly in younger specimens, not 

 in older. Fourth part short, slightly longer than second part, curved 

 inward slightly at distal end, with distinct, toothlike denticulations 

 along inner margin of older specimens, denticulations not visible in 

 younger specimens (figs. 20l,m). 



Postoral process of early encysted specimens mound-shaped swelling 

 adjacent to base of mouth cone, with two small, lobate protrusions on 

 anterior surface and single, small, apical projection bearing three 

 setules on posterior distal surface (fig. 20o) . 



Postoral process of late encysted and recently excysted specimens 

 bulbous protrusion adjacent to base of mouth cone. Distal surface of 

 process larger than proximal, with single spine projecting from posterior 

 distal surface, two setules from anterior proximal surface and single 

 knob from anterior distal surface, arising from slight depression in 

 surface. Wilson (1924) notes three setules instead of two from the 

 anterior proximal surface and does not mention the spine found on 

 the presently described specimens (fig. 20p). 



Maxilla of early encysted forms two-segmented, both segments 

 flaccid. Fh-st segment with almost parallel lateral margins, no 

 articular surfaces visible. Second segment tapered to blunt tip in 

 younger specimen, rounded but sharper tip in older specimen; length 

 of segment about half that of first segment in younger specimen, 

 two-thirds that of first segment in older specimen. Distal end of 

 second segment in both specimens tipped by small, pointed protrusion; 

 younger specimen with additional, setule-like structure on outer 

 distal corner, structure not present in older specimen (fig. 20g). 



Maxilla of late encysted specimens two-segmented. First segment 

 strongly developed, with long projection of middle of proximal surface 

 as articular surface. Lateral margins of first segment flatly convex; 

 middle of distal surface projecting as articular surface, middle of distal 



