206 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 24 



lightly striate and thickly covered with short plumose hairs on lobe, rest 

 of surface smooth and devoid of hairs. Carpus about one and a half 

 times as long as wide, anterior margin forming a low curve ; dorsal sur- 

 face covered with small flattened granules, appearing almost smooth, 

 and with traces of pubescence; ventral surface nearly smooth, proximal 

 half with a tuft of plumose hairs, this tuft showing from dorsal side 

 beyond anterior margin. Hand and fingers nearly smooth dorsally and 

 ventrally as in carpus, lying on a vertical plane with inner margin of 

 hand uppermost and fingers opening and closing vertically. Hand slen- 

 der, dorsal surface swollen and with traces of pubescence; outer (lower) 

 margin rounded. Fingers about half as long as palm, hooked and cross- 

 ing at tips, dactylus strongly curved ; gape with short plumose hairs, 

 extending nearly to tips of fingers and onto ventral surface of palm, 

 a few longer non-plumose hairs interspersed with plumose ones. 



Walking legs long and slender, nearly smooth, covered with scat- 

 tered, short non-plumose setae. 



Telson of abdomen with five plates. 



Measurements: Ovigerous female holotype: length 6.0 mm, breadth 

 4.7 mm. 



Color: No traces of the original coloration remain in the unique 

 specimen. 



Ecology: The holotype was dredged in 10-25 fathoms, "with basket- 

 stars" according to the accompanying label. The basket stars taken at 

 station 719-37 were Astrocaneum spinosum (Lyman). The crab was 

 probably, although not certainly, attached to the ophiuran. Further col- 

 lections will be necessary to determine whether a commensal relation- 

 ship actually exists. 



The type specimen, which was collected in late March, bears a large 

 number of well-developed eggs. 



Remarks: The type is unfortunately soft-shelled and consequently 

 some of the normal characters of the species may be obscured. This is 

 especially true of the propodus and dactylus of the walking legs, which 

 do not appear, even under high magnification, to bear supplementary 

 movable spinules on their lower margins. Structures resembling small 

 spinules could be made out on some of the legs, but these may simply 

 be setae. If Porcellana corbicola actually has such spinules they are 

 greatly reduced in number and size, a feature uncharacteristic of the 

 typical Porcellana species, as are the five-plated telson and the vertical 

 position of the hand and fingers. 



