COMPLETE HAIG: EASTERN PACIFIC PORCELLANIDAE 157 



One of the specimens examined, an ovigerous female from San Fran- 

 cisco, Panama, had the walking legs infested by a rhizocephalan 

 ( Thompsonia sp. ) . 



Range: Isla Tiburon, Gulf of California, south to Bahia de Santa 

 Elena, Ecuador; Isla Isabel, Mexico. Shore to 4 fathoms. 



Pachycheles trichotus, new species 

 Plate 12 ; plate 32, fig. 3 



Types: Holotype, male, U. S. National Museum Cat. No. 102412, 

 from Isla Verde, Panama; January 9, 1939; collected by students of 

 Elinor D. Robson. Paratypes: Acajutla, El Salvador; April 23, 1912; 

 collected by R. Paessler; two ovigerous females (Hamburg Museum 

 Cat. No. K26836). 



Diagnosis: Carapace with a few short plumose and non-plumose 

 hairs on front; carpus nearly smooth except near posterior margin, cov- 

 ered with short non-plumose setae and with a few long plumose hairs 

 at posterior margin, anterior margin with two teeth; manus nearly 

 smooth, covered with short non-plumose setae, outer margin with a few 

 long plumose hairs ; walking legs with long plumose hairs ; telson seven- 

 plated in males, incompletely so in females; no pleopods in male. 



Description: Carapace slightly (1.1 times) broader than long, sur- 

 face uneven, regions distinct, plicate on posterolateral and frontal re- 

 gions, otherwise smooth or punctate; front covered with a few very 

 short plumose and non-plumose hairs, traces of hairs occurring else- 

 where anteriorly. Front rounded in dorsal view, faintly trilobate in 

 frontal view, the median lobe slightly produced. Outer orbital angle pro- 

 duced into a small, distinct tooth. Separated portion of side wall con- 

 sisting of one large piece. 



First movable segment of antenna with a small, broadly rounded, 

 anterior projection; second and third nearly smooth; flagellum naked. 

 Outer maxillipeds lightly rugose. 



Merus of cheliped with short rugae or small flattened granules on 

 dorsal surface; anterior margin with a large, rugose, subtriangular 

 lobe on anterior margin, finely serrate on edge; ventral surface smooth. 

 Carpus armed on anterior margin with two distinct, serrate-edged teeth, 

 about equal in size, a trace of a third tooth sometimes present; teeth 

 and anterior half of dorsal surface nearly smooth, posterior proximal 

 half with two longitudinal rows of strongly projecting small granules; 

 a double row of similar granules along posterior margin; surface cov- 



