PART 1 GARTH : PACIFIC OXYRHYNCHA 289 



Material examined: Through the courtesy of Dr. Elisabeth Deich- 

 mann of the Museum of Comparative Zoology, Harvard, it has been 

 possible to obtain on loan the right first pleopod of the unique male 

 holotype. 



Measurements: Male holotype: length without rostral horns 45 mm, 

 width 38 mm, length of rostral horns 12 mm, length of branchial spine 

 7 mm. (Faxon) 



Color in life: Unknown. 



Remarks: The similarity of the male first pleopod (see Plate Q, fig. 

 7) to that of Rochinia rissoana (Roux), type of the genus, is striking. 

 The writer is indebted to Dr. Isabella Gordon of the British Museum 

 (Natural History) for a camera lucida sketch of the male first pleopod 

 of the latter species, made from a specimen in the Norman collection. 



Genus LIBIDOCLAEA Milne Edwards and Lucas 



Libidoclaea Milne Edwards and Lucas, 1843, p. 6. Rathbun, 1925, p. 

 223. 



Type: Libidoclaea granaria Milne Edwards and Lucas, by mon- 

 otypy. 



Description : Carapace pyriform, convex above, and laterally rounded 

 due to expansion of branchial regions; gastric region distinct, elongate; 

 genital region small and triangular, invaded posteriorly by the branchial 

 regions, separated from one another by a deep depression; cardiac and 

 intestinal regions indistinct and very oblique; hepatic regions rudimen- 

 tary. Surface covered with fine granulations and spinous tubercles, the 

 longest occupying the branchial, cardiac, and intestinal regions. Rostrum 

 elongate, narrow, and notched at extremity. Orbits divided above and 

 below by a groove; a strong preorbital spine. Eyes short, stout, and re- 

 tractile. Basal antennal article well developed, a strong tooth near mid- 

 dle of external margin. Buccal cavity closed by third maxillipeds. Sternal 

 plastron broader than long, anterior portion oblique. Chelipeds elongate, 

 robust, not surpassing next pair of legs; fingers elongate, slender, and 

 internally denticulate. Ambulatory legs slender, diminishing progressively 

 in length ; dactyli slender, elongate, and slightly curved. 



Abdomen of the male [and of the female] composed of seven seg- 

 ments. (After Milne Edwards and Lucas) 



Range: From Valparaiso, Chile, to Gulf of San Matias, Argentina. 

 10-1050 fathoms. 



