112 



BULLETIN 129, UNITED STATES NATIONAL MUSEUM 



DescHption. — Carapace covered with curved hairs and coarse 

 granulation except in the deep interregional furrows which are 

 smooth; granules less numerous on gastric and frontal regions. 

 Spines of gastric and cardiac regions stout, spine of first abdominal 

 segment slenderer. Rostrum narrow, advanced, hood-shaped, edge 

 arcuate, a median keel, and a very short, closed, median incision at 

 the end in the male. In the female the rostrum is narrower and 

 without incision. In the type male described by Edwards the ros- 

 trum was more pointed and not incised. Basal antennal article long 

 and narrow, inner lamina not deep, subentire, ending in a lobe, outer 

 margin obscurely denticulate, terminal lobe elongate. Postorbital 

 lobe large, advanced, its margins parallel in basal half, its inner 

 margin then becoming transverse. Male sternum and female abdo- 

 men covered with fine granules. 



Fig. 34.— Collodes rostratus. o. Rostrum of female (21865), X 16.66. 6. Rostrum of male (21864) 

 X 13.33. c. Left chela of male (21864), X 10.66 



Chelipeds feeble, merus and carpus and upper surface of manus 

 finely roughened, fingers gaping for two-thirds their length, basal 

 two-fifths of fixed finger hollowed on its prehensile edge in male. 



Variation. — Three small specimens, one of which is from the type- 

 locality, differ from t3rpical rostratus in having the rostrum split for 

 a short distance into two small .horns. As the other characters are 

 so close to rostratus, it is very probable that the bifid form is the 

 early form and that the horns disappear with age leaving an entire 

 rostrum, which may show slight indication of a bilobed tip. 



Measurements. — Male (21864), length of carapace 11.6, width 8.4, 

 length of cheliped 12, length of first ambulatory leg 20 mm. Female 

 (21865), length of carapace 11.7, v/idth 9 mm. Male (2049), length 

 20.1, width 15.6 mm. Female (2057), length 7, width 5.2 mm. 



Range. — From Cape Frio, Brazil, to Gulf of San Matias, Patagonia. 

 Depth, lOH to 52 fathoms. 



Material examined. — See table, page 111, 





