70 Addis on E. V err ill, 



moves more transversely ; it is also thicker, especially at the end, 

 and its lateral surface is more curved or twisted (pi. 24, figs. 5, 6). 

 corresponding to somewhat different forms of the lobes on the 

 fixed finger. 



The smaller chela is also stouter and more complex than in the 

 Bermuda species, for it has more of the notches and grooves seen 

 in the larger chela, only they are less developed ; even the charac- 

 teristic subdorsal groove of the palm is present, in a reduced form ; 

 its dactyl is slightly oblique ; the inner surface is hairy, the outer 

 nearly smooth. Both species have a long, acute basicerite. The 

 frontal spines and antennal scales and spines show no very tangible 

 differences. The telson and uropods are nearly the same in the 

 two forms. In both species the propodus of the ambulatory legs 

 has six pairs of spines on the under side ; the dactyls are biun- 

 guiculate in both. 



Alpheus bahamensis (Rankin). Purple-clawed Snapping Shrimp. 



Alpheus hippothoc var. bahamensis Rankin, Annals N. York Acad. 

 Sciences, vol. xi, p. 247, pi. xxx, fig. 5, 1898 ; op. cit., vol. xii, p. 539, 

 1900 (Bermuda). 



PLATE XX, FIGURES 6, 6a, (photos, cotype.) PLATE XXVIII, FIGURES i, a-1, 

 2, 3-3! (details). By A. H. V. 



The following description and the figures are made chiefly from 

 a cotype of this species sent to me by Dr. Rankin. It was taken 

 at St. David's Island in 1897. Our other Bermuda specimens 

 agree perfectly with it. 



Rostrum small, not concave above, sloping anteriorly, laterally 

 compressed, very thin, the front part triangular in a side view, 

 projecting but little beyond the orbital lobes ; between rostrum and 

 eyes is a shallow fossa, about two-thirds as wide as the eyes, and 

 terminating in a regularly incurved shallow emargination of the 

 front edge, between rostrum and orbital lobes and fading out grad- 

 ually posteriorly. Eyes swollen, the orbital lobe is prominent and 

 faintly bilobed in front, without a denticle ; edge strongly emargi- 

 nate below the eyes. 



Antennular scale small and narrow, its spine scarcely reaching 

 the second segment ; second segment hairy, about twice as long as 

 third segment. Basal segment of antennae not distinctly denticu- 

 lated on its outer margin; its spine minute or rudimentary. 



