542 CRUSTACEA. 



similar differences exist as regards the other joints. The third joint 

 of the third and fourth pairs of legs often has a tooth on the lower 

 apex, although unarmed in most species. 



We separate from Alpheus the species without a beak, in which 

 the hands of the anterior legs have a partially reversed position, 

 the lower margin being either inward or upward, so that the move- 

 able finger is below or outside. Of these we have made the genus 

 Betaeus. 



I. ROSTRUM MARGINE FRONTIS ORTUM, SQPERFICIE INTER OCULOS S^EPIUS LEVITER 



CARINATA. 



A. Antennarum articulus Imus externarum spina externa sive nulla sive obsolescente 



armatus. 



1. Manus marginibus inferiore svperioreque versus digilos excavata. Dens antennarum internamm 

 basalts articulo \monon longioT. Articulus pedum QtiorumQtius omnino inermis. 



a. Orbitse margo inermis. 



ALPHEUS EDWARDSII, Audouin. 



Plate 34, fig. 2 a, front and antennae, much enlarged ; 6, extremity 

 of outer maxillipeds ; c, larger hand (right) ; d, smaller hand ; e, part 

 of second pair of feet ; /, part of third or fourth pair. 



Cape Verdes, Island of St. Jago. 



The species agree closely with the original figure in the work on 

 Egypt, Plate 10, fig. 1, but not with Edwards's description, which 

 represents the orbital margin as armed with a spine as long nearly as 

 the beak, instead of arcuate and unarmed. The second joint of the 

 inner antennas is about one and a half times as long as either the 

 first, or the third. The lamellar spine or tooth at the outer base of 

 the inner antennas extends to apex of first joint. Moveable scale of 

 outer antennas as long as base of inner antennas, and shorter than 

 base of outer. Legs rather long. Larger hand very stout, outer 

 surface of hand having a sinuous furrow, extending backward from 

 below the sinus in the superior margin ; lower margin rounded ; fingers 

 short and stout and furnished with a few hairs principally towards 



