SHRIMPS OF THE GENUS BETAEUS — HART 455 



bearing movable spine on proximal lower margin; sparsely setose. 

 Merus and propodus subequal in length. Spines on carpus and pro- 

 podus small, with fine seta beside each spine. Narrow bifid dactyliis 

 (fig. 78) with inconspicuous setae at base of claws. 



Fourth leg similar but smaller than third. 



Fifth leg well developed, but ischium and merus slightly shorter 

 than those of third leg, no movable spine present. No spines on 

 carpus, few on propodus, but usual brush on distal part of propodus. 

 Dactylus longer, more slender than others but similarly bifid. 



First pleopod with endopodite short and round at tip. Second 

 pleopod with endopodite subequal to exopodite, appendLx interna 

 straplike. 



Uropod (fig. 65) longer than telson. Posterior margin of peduncle 

 produced into two teeth, with setae on curved margin between. 

 Outer tooth longer. Lateral margin of exopodite ends in small tooth 

 covering base of large spine, nearly as long as terminal portion. 



Male. — Similar to female except tip of stylocerite reaches to end 

 of second segment of antennular peduncle. Left chela with decided 

 gape, large triangular tooth on fixed finger, intermeshing smaller 

 teeth on both fingers. Right chela with gape composed of round 

 hiatuses. Second pleopod with appendix masculina bristled on distal 

 half, terminally on blunt tip. 



Color. — Pale olive-green (Hilton, 1916). Specimen label: "green 

 eyes." 



Size. — Carapace length of smallest ovigerous female 6 mm.; 

 largest female 8 mm.; male 6 mm. Length of chela of largest female 

 8 mm. ; of male 6 mm. 



Range. — Laguna Beach to Monterey Bay, Calif. 



Habitat.— Kelp holdfasts (Hilton 1916). 



Material. — The following specimens were examined: 



California. — Laguna Beach, W. A. Hilton, 1 ovigerous female holotype 

 (USNM 48933), 1 ovigerous female (USNM 108230).— Pacific Grove, January 

 1928, G. E. MacGinitie, 1 specimen.— Monterey Bay, China Point, shore, June 

 1908, 1 ovigerous female, 1 male (Hopkins Marine Station). 



Notes. — ^This species may be confused with Betaeus setosus, but it 

 has much shorter antennules and antennae, is more slender and less 

 setose. The chelae of the female from China Point are toothed like 

 those of the male: intermeshing, with the hiatuses coinciding to form 

 a foramen. Ovigerous females have been taken in June. The eggs 

 are translucent gi"een (HUton, 1916). 



Betaeus setosus, new species 



Figures 52, 53, 57, 68-72, 79, 80; Plate 2 

 Alpheus aequalis Holmes, 1900, p. 189 Cpart, free-living form). 



