66 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 24 



Walking legs rugose, all segments with plumose and non-plumose 

 hairs. Merus unarmed, that of leg 3 not inflated. 



Material examined: See Table 16. 



Measurements: Males, 4.3 to 20.0 mm; non-ovlgerous females, 4.4 

 to 18.2 mm; ovigerous females, 7.8 to 18.9 mm. Guerin reported the 

 maximum length to be about 20 mm. H. Milne Edwards gave 22.5 mm 

 for the length of Porcellana lobifrons, which was based on some of the 

 same specimens from which Guerin described P. tuberculata. Targioni- 

 Tozzetti (1877) gave a length of 22 mm for a male specimen. 



Color: Brownish red with a tinge of purple; prominent surfaces of 

 the carapace blue with a purplish tinge; purplish below. (Dana) 



Ecology: Taken under stones in the littoral. Lund University 

 Chile Expedition specimens were collected in the lower and middle 

 tidal zone, and (on one occasion) from holdfasts of a brown alga. 



Ovigerous females have been collected in January, February, June, 

 August, and November. 



Relationships: Petrolisthes tuberculatus is apparently not closely 

 related to any species except P. tuberculosus (H. Milne Edwards). 



Remarks: Three of Guerin's type specimens from Valparaiso were 

 seen in the Academy of Natural Sciences of Philadelphia, which also 

 houses one specimen from the U. S. Exploring Expedition, labelled 

 "Peru" (probably San Lorenzo). 



Range: San Lorenzo, Peru, south to Bahia de San Vincente, 

 Chile. 



Petrolisthes tuberculosus (H. Milne Edwards) 

 Plate 24, fig. 4; text-fig. 3(2) 



Porcellana affinis Guerin, 1835, p. 116 (type locality, Chile). Preoc- 

 cupied by Porcellana affinis Gray, 1831. 



Porcellana tuberculosa H. Milne Edwards, 1837, p. 256 (type locality, 

 shores of Chile). Guerin, 1838b, p. 8; 1839, p. 176. Nicolet, 

 1849, p. 194. 



Porcellana tuberculifrons H. Milne Edwards and Lucas, 1843, p. 33 

 (new name). Dana, 1852, p. 422. Cunningham, 1871, p. 495. Not 

 Nicolet, 1849, p. 193. 



Porcellana desmarestii, White, 1847, p. 62. Not Petrolisthes desmarestii 

 (Guerin). 



