OXYSTOMATOUS AND ALLIED CRABS OF AMERICA I'JQ 



slightly convex surfaces and are mounted on short thickened stalks 

 like mushrooms. On the anterior third a median ridge extends 

 from the front across the gastric region; on either side is a hollow; 

 surface covered with depressed granules. Hepatic region convex; 

 pterygostomian region bluntly angular; neither is armed. Intesti- 

 nal region distinctly outlined. Posterior margin with two broad 

 rounded tuberculate lobes; posterolateral margin of branchial region 

 with a smaller tuberculate lobe. Frontal margin with a blunt tooth 

 at either end. Abdomen and sternum covered with beadlike tubercles ; 

 the maxillipeds with large irregular tubercles. The branchial chan- 

 nels are equally advanced with the orbital wall, margin entire. 

 Chehpeds covered with tubercles similar to those of carapace; the 

 largest ones on merus and outer surface of carpus and propodus. 

 Length of merus about equal to wddth of carapace ; dactylus less than 

 two-thirds length of outer margin of propodus; latter rather narrow, 

 width less than half exterior length. Legs granulate, with marginal 

 rows of mushroom granules. 



Measurements. — Largest male, median length 9.2, width 9 mm; 

 larger female, median length 8.2, width 8.1 mm. 



Range. — Mexico to Ecuador; 3 to 55 fathoms. 



Material examined. — See table 56, page 181. 



RANDALLIA MINUTA Rathbun 



Plate 84 

 RandalUa minuta Rathbun, Proc. Biol. Soc. Washington, vol. 48, p. 2, 1935. 



Type locality. —Puerto Culebra, Costa Rica ; dredging around isles 

 in bay; February 25, 1934; station 257, Velero III, Hancock Galapagos 

 Expedition; 1 male (U.S.N.M. no. 69745). 



Diagnosis. — Size small. A smooth cap over the bidentate front. 

 A raised flat plate on hepatic region. Four minute posterior promi- 

 nences in male, absent in female. 



Description. — Male: Carapace coarsely granulate except in the 

 depressions between regions, and the front and hepatic region. These 

 last are elevated and nearly smooth; the cap over the front has tvvo 

 teeth projecting forward and two backward, which are directly behind 

 the front teeth. The hepatic region is covered by a round flat plate. 

 Two small shallow lobes on posterior margin, and an equally small but 

 more pointed lobe on posterolateral margin. Lower surface granulate. 

 Merus of chelipeds coarsely granulate, carpus and manus finely so. 



Ovigerous female: Posterior margin straight and adjacent margin 

 slightly concave; neither has projecting lobes or teeth. Margin of 

 posterior lobes of frontal cap more rounded than in male. 



Measurements. — Male, length of carapace 4, width 4.2, length of 

 manus 1.7, width 1 mm. Female, length of carapace 4.5, width 

 4.7 mm. 



