124 UNITED STATES NATIONAL MUSEUM BULLETIN 29 6 



No distinct orificial knob was seen, although a thickened and 

 wrinkled area dorsal to the aperture could be homologous. 



The head is rounded and scaly, without hairs or bristles. A large 

 labrum extends from the mouth field to the aperture, as is typical 

 for the genus. The mouthparts consist of the typical mandible Avith 

 palp and two pairs of maxillae. 



The mandible is delicate, with numerous extremely fine teeth that 

 are easily broken in study. No bristles or hairs were seen. The palp is 

 closely adpressed to the labrum in a typical manner and appearance. 

 The first maxilla also is very weak, with no strong teeth, but numerous 

 heavy bristles arising from a blunt end. The apodeme is long and 

 curved, with the widening at the curve not as pronounced as the "keel" 

 in some forms. 



The second maxilla is typical. 



A paired mouth cirrus is present, but is reduced to a pair of small, 

 unsegmented processes bearing a few bristles. 



There are four pairs of biramous terminal cirri and no caudal ap- 

 pendage. The terminal cirri are similar, with an oblique suture dividing 

 the two segments of the protopod. The dorsal surface of the base of 

 each terminal cirrus bears small granular knobs basally and a patch of 

 small hairs distally. 



The segment count for each cirrus follows: 



Cirrus: 2 (first 3 4 5 



terminal) 



Ramus: ante- poste- ante- post- ante- poste- ante- poste- 



rior rior rior rior rior rior rior rior 



Segments: 13 18 22 25 25 29 25 25 



The number of any of these rami will vary about five segments between 

 different specimens. 



The setation on the terminal cirri involves a pair in the middle and 

 distal ventral (lesser curvature) surface of each segment, and a single 

 bristle on the distal dorsal surface of each second to fifth segment. The 

 ventral setation is modified in that the pairs are equal, or nearly equal, 

 in length, rather than the typical condition with the medial pair being 

 much shorter than the distal pair. 



From the dorsal surface of the thorax extends a single body process, 

 probably homologous to the filamentary appendages of other barna- 

 cles. It is very thin skinned, and slightly lumpy, but not hairy or an- 

 nulated. 



The fine striations on the dorsal surface of the thorax are typical of 

 the order, but the distribution is somewhat more restricted in area 

 than is typical. 



