Mr. W. N. Lockington on American Alphei. 475 
equal in length to meros, smooth, ovate ; dactylus in the same 
plane with the hand; pollex slightly hooked at tip. 
Meros of larger hand less compressed than that of smaller ; 
a small spine at upper distal end; manus broad, stout, en- 
tirely smooth, ovate, terminating abruptly in a sinuate distal 
margin, from the lowest point of which projects the short, 
broad, spoon-shaped pollex. Dactylus short, stout, curved, 
overpassing the pollex, with a large basal tooth fitting into a 
groove in the latter. Dactylus and pollex of both hands 
blue, becoming black at the tips. Meros of second pair 
longer than the ischium; carpus five-jointed, first joint nearly 
as long as the other four; second, third, and fourth joints 
equal, and two of them equal to the fourth ; hand about equal 
to third and fourth joints. 
Meral joints of posterior pairs without spines; propodi 
spinulose beneath ; dactyli bifid at tip, the upper spine longer 
than the lower. ; 
Telson with sinuate margins, arcuate posteriorly. 
Length of largest specimen 30 millims., carapax 10, larger 
hand to tip of dactylus 11. ?. 
Several specimens from Port Escondido, Mulege Bay, and 
other points on the Californian shore of the Gulf of California. 
Alpheus sulcatus, Kingsley. 
Alpheus sulcatus, Kingsley, loc. cit. p. 193. 
Bay of Panama. Zorritas, Peru (f. H. Bradley). 
Alpheus heterochelis, Say. 
Alpheus heterochelis, Say, Journ. Acad. Nat. Sci. 1818, p. 243 ; Edwards, 
Hist. Nat. des Crust. tome ii. p. 856; De Kay, New-York Fauna, 
Crust. p. 26; Gibbes, Proc. Am. Assoc. Ady. Sci. p. 196; Kingsley, 
loc. cit. p. 194; Smith, Trans. Conn. Acad. ii. pp. 23, 39. 
Alpheus armillatus, Edwards, op. cit. i. p. 354. 
Alpheus lutarius, Saussure, Crust. Nouy. des Antilles et du Mexique, 
p- 40, pl. iii. f. 24, 25; Martens, Wiegmann’s Archiv fur Naturge- 
schichte, 1872, p. 189. 
Halopsyche lutaria, Saussure, Rev. Zool. 1857, p. 100 (teste Saussure). 
Halopsyche bispinosus ?, Streets, Proc. Ac. Nat. Sci. Phil. 1871, p. 242. 
This appears to be one of those forms, occasionally met 
with in every zoological class, that have changed so slightly 
in accommodating themselves to their environment as to be 
at once recognizable as the same species. ‘ 
Specimens collected in various localities in Lower California 
present no appreciable difference from the typical heterochelis, 
of which I have a specimen from Folrida. This specimen 
lacks the smaller hand. 
39% 
Oa 
