THE SPIDER CRABS OF AMERICA 



513 



Subgenus Parthenope 



Lamhrus A. Milne Edwards (restricted), Crust. R6g. Mex., 1878, p. 146; 



tj^pe, L. longimanus. — Miers, Challenger Rept., Zool., vol. 17, 1886, p. 



92 (part). — Alcock, Journ. Asiat. Soc. Bengal, vol. 64, 1895, p. 260. 

 Parthenope Rathbun, K. Danske Vidensk. Selsk. Skrifter, 7 Raekke, 



naturv. og math., Afd. 5, No. 4, 1910, p. 319. 



Carapace ovate-pentagonal or subcircular, with the surface granu- 

 lar or pustular and but little carinate in the adult; rostrum usually 

 exceedingly short. 



PARTHENOPE (PARTHENOPE) AG ON US (Stimpson) 



Plates 178 and 179; plate 275, figs. 1-3 



Lamhrus agonus Stimpsox, Bull. Mus. Comp. Zool., vol. 2, 1871, p. 131 

 (type-localities, off the Marquesas, off Carysfort Reef, oflf Conch Reef, 

 40 and 49 fathoms; types not extant). — A. Milne Edwards, Crust. 

 Reg. Mex., 1878, p. 151; 1879, pi. 28, figs. 3-3c. 



Diagnosis. — Carapace subcircular, A ventral spine on each 

 side opposite cheliped. Chelipeds very long; four or nearly four 

 times as long as carapace. Second segment 

 of abdomen conspicuously three-lobed. 



Description. — Carapace ovate-pentagonal 

 or subcircular, about one-fifth broader than 

 long, with rounded sides, without angles; 

 a moderate postorbital constriction, which, 

 however, does not involve a prominent, 

 dentate, pterygostomian ridge which con- 

 tinues from the lower orbit to a point 

 above the cheliped. Depressions between 

 regions not remarkably deep. Surface 

 coarsely punctate or eroded, and with 

 numerous granules and tubercles; the larger 

 tubercles more or less spiniform and arranged 

 as follows: Five on gastric region, of which 

 four are near the middle in a transverse 

 line, and the other, larger, on median line, 

 further back; three in a longitudinal row on 

 cardiac region; one on each side of urocardiac 



lobe; five on each branchial region, the posterior one being prolonged 

 in a spine; one on each hepatic region. The antero-lateral margin 

 of branchial region is armed with six small teeth; below and ])cliind 

 the last a broad triangular tooth; and still lower down and on the 

 ventral surface a stout spine visible between the ischia of the cheliped 

 and first leg. Median rostral tooth narrow and produced; a few 

 denticles at its base on either side, and an acute forward-pointing 

 tooth over each antennular cavity. Several spines on outer margin 

 of orbit and a small spine on upper surface of eye. 



Fig. 146.— Parthenope agonus 

 (51009), maxilliped, x 11.7 



