480 NATURALIST IJ^ CALIFORNIA. 



TrailUi) ; also, Ricburdson's Pewee {Contopus Ricliard- 

 sonii) and Black-cap Warbler (^Mijiodioctes pusillus) .* Tbe 

 only mammals I obtained were a small Bat ( VespertiUo Yu- 

 manensis?) , and tbe typical gray variety of Harris' Sper- 

 mopbile, sbot some miles from tbe river on Maj^ 28tb, tbe 

 day I started to retnrn to tbe coast. Tbe reptiles added 

 were tbe Colorado Toad {Biifo alvarius)^ an enormous 

 semiaquatic species nearly as smootb as a frog ; and several 

 otbers on tbe way westward wbicb do not ai3pear to inhabit 

 tbe valley. 



^ Fisb seemed to be scarce in tbis muddy river, and I only 

 obtained tbree sjDecies of cyprinoids : a large one called Col- 

 orado Salmon (^PtycJiocheilus lucius), a Gila (6r. robusiaf), 

 and one allied to tbe Suckers [Catostomus) . Mollusca were 

 equally rare, and a few specimens of tbe remarkable Physa 

 humerosa and PJanorbis amnion were all I found. My col- 

 lection of vertebrata made at Fort Mojave numbered 100 

 species, and 250 specimens. 



I migbt enumerate many otber species tlmt bave been ob- 

 tained in tbe Colorado Valley by otber collectors, but it 

 would be too long a list. I bave, altogetber, counted up 

 twenty-tbree species of mammals, one bundred and nine- 

 teen birds, and ten reptiles, as found tbere at various sea- 

 sons, some of wbicb I beard of as visiting Fort Mojave 

 later tban my stay tbere. By May 15tb tbe spring rains 

 w^ere over and tbe sbort vegetation of tbe mesas was drying 

 up. About tbis time also tbe river was rising rapidly, 

 bringing down cold water from tbe mountains, and moder- 

 ating tbe beat wbicb bad been as bigb as 116° in tbe sbade 

 on April 20tb. Tbe summer wind began to blow from tbe 

 south, and would, probably, bring some of tbe latest birds 

 witb it, wbile otbers would come after tbe floods to seek tbe 

 food left by tbe subsiding waters. Among tbese bave been 

 seen tbe strange Vulture-eagles (Poli/borus Audubonii and 



*On tlie 27th I saw the only one of the rare Western W&vhlev {Dendraca periden- 

 talis), and the first Sea-gi-een Swallows. 



