COMPLETE HAIG: EASTERN PACIFIC PORCELLANIDAE 225 



crests all defined by broad grooves; first crest the lowest, sometimes 

 obsolescent. Manus with three low longitudinal crests and a fourth along 

 outer margin, these crests defined by light grooves. Fingers straight, 

 lightly grooved in center, meeting for entire length or only slightly 

 gaping; gape naked or with traces of pubescence. 



Walking legs rather short and stout, covered with small, low gran- 

 ules. Merus with a short anterior fringe of plumose hairs; all segments 

 with long, scattered non-plumose setae. 



Telson of abdomen with seven plates. 



Measurements: Holotype male: length 5.6 mm, width 5.4 mm. Para- 

 types: males, 4.9 to 5.3 mm; non-ovigerous female, 4.7 mm; ovigerous 

 females, 4.2 to 4.8 mm. 



Color: No trace of color remained in any of the specimens examined. 



Ecology: All the material was taken in the intertidal zone, appar- 

 ently under stones. Ovigerous females collected in January were in- 

 cluded in the lot from Peru. 



Relationships: Megalobrachium peruvianurn is most closely allied 

 to a western Atlantic species, M. roseum (Rathbun), 1900. In the latter 

 form the posterolateral angles of the carapace are more posteriorly lo- 

 cated, and the anterolateral margins diverge slightly to these angles, 

 instead of being subparallel as in M. periivianuni ; there are a few small 

 tubercles on the carapace surface; the crests on the chelipeds are higher 

 and tend to become tuberculate; and the walking legs are somewhat 

 nodulate. The telson of the abdomen is seven-plated in both species. 



Remarks: Among material examined by the writer during prepara- 

 tion of a report on the Anomura of Chile (Haig, 1955) was the Ham- 

 burg Museum specimen from Junin, listed above. This was recognized 

 at the time as an undescribed species, but was not included in the re- 

 port on Chilean Anomura; it was believed that the Junin record was 

 erroneous, since Megalobrachium is typically a tropical genus. Subse- 

 quently the Hancock Foundation specimens from Peru have become 

 available for examination. The Junin record may now be accepted as 

 correct, and another species added to the Chilean anomuran fauna. 



The name peruvianum was chosen for this species because of its 

 surprising occurrence in the Peruvian faunal province. 



Range: Known only from the two localities listed above, Islas Lobos 

 de Afuera, Peru, and Junin, Chile. 



