60 U.S. NATIONAL MUSEUM BULLETIN 2 95 



Paranesidea. It is very similar in these respects to Bairdia serrate 

 Miiller, 1894, and Bairdia roqiiebrunensis Rome, 1942. From thest 

 two species it differs by a much more steeply arched dorsum and bj 

 the 6 furcal setae, all long (B. serrata has 5 long, 2 short; B. roque- 

 hrunensis has 5 long, 3 short). 



Triebelina van den Bold, 1946 



Triebelina van den Bold, 1946, pp. 23, 73. — Triebel, 194S, p. 17. — van Morkhoven; 

 1963, p. 34. 



Type-species. — Triebelina indopacifica van den Bold, 1946, p. 74 

 fig. 7. 



Diagnosis. — Carapace extremely robust and with exterior ornament 

 of reticulation and usually other ridges and swellings, valves of 

 distinctly different shape and ornament pattern; hinge elements 

 smooth; muscle-scar pattern consists of 8 irregularly elongate scars 

 arranged in 4 parallel diagonal rows. 



Female antenna with anterodistal seta about two-thirds the length 

 of distal claw and slightly thickened; 4 featherless setae of branchial 

 plate of first thoracic leg segregated proximally, the first one longest; 

 distal claws of antenna and legs tending to be barbed. 



Description. — Carapace more robust for its relatively small size 

 than any other group of Bairdiidae, with left valve very much higher ■ 

 than right valve dorsally, of a more subquadrate shape, and with 

 different lateral pattern of ornamental ridges. Lateral outline of left 

 valve varying from elongate-hexagonal to rhomboidal; right valve 

 with distinctly more produced posterior. Surface deeply pitted in 

 reticulate arrangement, may also have dorsomarginal and ventrolateral 

 thickened crests, nodes, and other swellings. Venter flattened, greatest 

 thickness located near venter. All margins generally edged with 

 abundant thick spines. Hinge simple but deeply incised, all elements 

 smooth. Muscle-scar pattern composed of 8 elongate scars of irregular 

 outline arranged in four evenly spaced jnirallel rows aligned diagonally 

 at an angle of as much as 45° in right valve, left pattern similar but 

 less steeply tilted and less distorted, showing more visibly its homol- 

 ogies with Paranesidea. 



Appendage characters generally very similar to Paranesidea. Female 

 antenna with distal claw abruptly curved and barbed at its tip, 

 anterodistal seta two-thirds the length of distal claw and equal in 

 thickness to posterodistal seta of podomere 5, fused claw of podomere 

 6 smooth except for barbed tip. Thoracic legs of female fairly thick and 

 with distally barbed claws; 4 featherless setae of vibratory plate of 

 first leg segregated proximally, the first seta being slightly longer and 

 thicker than the others, which are of equal size. Some setae of maxillar 



i 



