174 BULLETIN 152, UNITED STATES NATIONAL MUSEUM 



advanced, tridentate. Ocular peduncles elongate, slender, stout at 

 base, situated in small orbits. The second or basal article of the 

 antenna is soldered to the Infero-external surface of the frontal 

 tooth along with the two last peduncular articles; at the end of the 

 peduncle may be seen a rudimentary flagellum formed of two or 

 three extremely short and narrow articles which are soldered to the 

 peduncle and to each other and which seem also to be glued to the 

 same surface of the frontal tooth. Buccal area longer than broad, 

 narrowed forward; outer maxillipeds elongate, obliquely placed. 

 Legs narrow, of moderate length. Male abdomen narrow, third, 

 fourth, and fifth segments fused. 

 Contains only one species. 



CORYSTOIDES CHILENSIS Milne Edwards and Lucas 



Plate 78 



Corystoides chilensis Milne Edwards and Lucas, d'Orbigny's Voy. I'Amer. 

 Merid., vol. 6, pt. 1, 1844, p. 32; atlas, vol. 9, 1847, pi. 16, figs. 1-le (type- 

 locality, coasts of Valparaiso; type in Paris Museum). — Nicolet, in Gay, 

 Hist. Chile, ZooL, vol. 3, Crust., 1849, p. 179.— Porter, Revista Chilena 

 Hist. Nat., vol. 22, 1918, p. 52. 

 Corystoides abhreviaius A. Milne Edwards, Bull. Mus. Corap. ZooL, vol. 8, 1880, 

 p. 20 (type-locality, Rio de la Plata, below Montevideo; cotypes in M.C.Z., 

 Paris Mus., and U.S.N.M.). — Bouvier, in A. Milne Edwards and Bouviek, 

 Mem. Mus. Comp. Zool., vol. 47, 1923, p. 309, pi. 2, fig. 7; pi. 4, fig. 6; pi. 5, 

 fig- 1- 

 Diagnosis. — Anterior half of carapace wider than posterior half and 

 bearing conspicuous raised bead granules. Pterygostomian region 

 not advanced beyond the line of the front. Dactyli of legs slender. 



Description. — Carapace irregularly granulate anteriorly and at the 

 sides, posteriorly almost smooth; some depressions in the median line. 

 Antero-lateral borders armed with six teeth on each side, third and 

 fourth most pronounced, second and sixth reduced; these teeth and 

 those which form the front are finely granulate on the upper edge, with 

 a large bead granule at the tip of each tooth, except the median ros- 

 tral tooth which has two beads side by side. Antennules ciHated. 

 Pterygostomian region very prominent and gi-anulated. Outer 

 maxillipeds finel}" punctate, ischium with a longitudinal groove, 

 Chelipeds finely granulate except the first three articles which are 

 smooth; fingers long, curved, strongly denticulate on inner margin. 

 Legs smooth, ciliated. Sternum finely punctate. 



Color. — Yellowish white (Milne Edwards and Lucas). Bright red, 

 in life (Porter). 



Measurements.— Length of carapace 27, width of same 22 mm. 

 (Milne Edwards and Lucas). Male, length 18, width 16 mm. (Bou- 

 vier for chilensis). Male, length 20, width 18 mm. (Milne Edwards 

 and Bouvier for abbreriatus). 



