40 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 24 



striations. Front triangular, truncate at tip, with a deep median sulcus 

 extending to protogastric lobes; a small supraocular spine, scarcely 

 distinct in larger specimens. Postorbital angle produced into a small 

 spine. An epibranchial spine at cervical groove, followed by a second 

 spine on epibranchial region between cervical and mesobranchial 

 grooves. 



First movable segment of antenna with a small, spine-tipped, lamel- 

 lar lobe ; second and third nearly smooth ; flagellum naked. Outer maxil- 

 lipeds rugose. 



Chelipeds covered with piliferous striations, granulate on their 

 margins. Merus with a large serrate-edged tooth on anterior margin. 

 Carpus less than twice as long as wide, anterior margin with a row of 

 four or five broad, serrate-edged teeth ; striations continuing obliquely 

 and unbroken across dorsal surface. Manus broad, flattened, striations 

 continuing obliquely and unbroken across dorsal surface except on 

 margins, there breaking up into flattened tubercles; outer half of 

 manus often with a fringe of hairs. Gape of fingers nearly smooth, 

 devoid of pubescence. 



Walking legs faintly rugose; merus with a fringe of plumose hairs 

 on anterior margin, all segments covered with long, non-plumose setae; 

 anterior margin of merus of leg 1 with seven or eight spines, of leg 2 

 with eight to ten, of leg 3 with six or seven ; merus of legs 1 and 2 with 

 a posterodistal spine, a second occasionally present. 



Ventral surface of chelipeds striate; abdomen and ventral surface 

 of walking legs nearly smooth. 



Material examined: See Table 7. 



Measurements: Males, 3.9 to 11.0 mm; non-ovigerous females, 4.0 

 to 10.2 mm; ovigerous females, 4.7 to 9.2 mm. The male holotype 

 measures 11.0 mm in length, 10.1 mm in breadth. 



Color: In alcohol most specimens are strikingly marked, with a 

 strong stripe of deep purplish-red along each striation of the carapace, 

 and stripes across the metabranchial and frontal regions. The chelipeds 

 are similarly striped, and the walking legs and abdomen are striped 

 or spotted. (Haig, 1957a) The ventral surface of the chelipeds and walk- 

 ing legs is usually solid dark purplish-red. 



Ecology: Petrolisthes glasselli is usually associated with corals; it 

 has been recorded from Pocillopora and Pavona in the littoral and to 

 about 4 fathoms. It has been taken a very few times under stones, but 

 probably always remains close to corals. 



