426 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.21 



2b. Tooth in gape of mature male cheliped tricuspid. Spines of 

 meri of walking legs reduced to granules or wanting. Outer 



row of excavations on arm obsolescent 



sulcata panamensis 



Thoe erosa Bell 



Thoe erosa Bell, 1835b, p. 171 ; 1836, p. 48, pi. 9, fig. 4, 4k-o. Nobili, 

 1901, p. 30. Rathbun, 1910, p. 575 (part: not Panama); 1925, 

 p. 351, pi. 249, figs. 1-6. Boone, 1927, p. 149, text-fig. 145. Garth, 

 1946, p. 386. 



Type: Syntypes of both sexes, originally deposited in the Museum of 

 the Zoological Society [London] and Bell Museum, no longer extant. 

 Length of measured syntype 10.6 mm, width 8.5 mm. 



Type locality : Galapagos Islands, 7 fathoms, sandy mud ; Hugh 

 Cuming, collector. 



Localities subsequently reported, with collectors: Ecuador: Santa 

 Elena Bay, E. Festa (Nobili). 



Atlantic analogue: None. 



Diagnosis: Only one anterior tooth or lobe on basal antennal article. 

 A double row of deep excavations on arm. Fingers strongly arched ; gape 

 entire except for one tooth on dactyl. 



Description: Carapace somewhat triangular, longer than broad, 

 rounded behind, depressed, horizontal, covered with low tuberosities; 

 the lateral margin without teeth, perpendicular. Rostrum minute, taper- 

 ing to the point, point slightly divided. Orbits nearly round, without 

 teeth, with three small fissures, one above the inner canthus, another at 

 the outer angle, and the third beneath. Eyes subretractile, globose, 

 smaller than the base of the peduncle. [Antennules] lodged in a fossa, 

 anteriorly divided by a tooth projecting backwards and longitudinally 

 excavated. [Antennae] with the basilar [article] very broad, produced 

 forward and backwards, the movable portion three times as long as the 

 rostrum and ciliated on the inner side. External [maxillipeds] with the 

 [exognath] expanded at the outer margin; [ischium] of [endognath] 

 nearly rhomboidal, with entire margins, ciliated on the inner margin ; 

 [merus] without any emargination for the insertion of the palp. 



[Chelipeds] in the male longer and much more robust than the 

 [ambulatory legs]. The arm with a [double] series of quadrilateral 

 excavations on the upper and outer surfaces diminishing backwards. 

 Hands smooth, carinated beneath, the fingers meeting only at the point, 



