NO. 1659. AMERICAN SPECIES OF SYNALPIIEUS—COVTIERE. 



43 



The small chela has these proportions: Fingers 1 ; total length 2.G; 

 height 1.08; it is 2.45 times smaller than the large chela; the 

 meropodite is a little more than twice as long as wide. Compared 

 to that of S. fi'dzDuiUi'i I, the small chela appears much stouter, and 

 it would probably be the same Avith S. sdiilucasL 



In the second pair, the first article of the carpus, the sum of the 

 four following ones, and the terminal chela are practically of the 

 same length; the carpus is G.5 times longer than wide. 



Fig. 24. — Synalpheus heroni. n, fbont.\l and antennal region; K, large chela; 



k', SMALL CIIELIPED OF FIRST PAIR ; 1, FOOT OF SECOND PAIR ; til, FOOT UF THIRD PAIR. 



The proportions of the third pair are : Meropodite 2 ; carpus 1 ; 

 propodite 1.6; the meropodite is 2.5 to 2.6 times longer than wide, 

 and is therefore longer and thicker than in the species from Lower 

 California. 



Cape St. Lucas, Lower California ; John Xantus ; type. Cat. No. 

 6355, U.S.N.M. 



BREVICARPUS Group. 



SYNALPHEUS MINUS (Say). 

 Alphcus minus Say, Journ. Acad. Nat. Sci. Pliila., I, ISIS, p. 245. 



Teeth of the frontal border in the form of an equilateral triangle, 

 the rostral tooth usually a little wider at the base, and sometimes very 

 slightly longer, than the lateral teeth. 



The proportions of the antennular articles are: 2, 1.5, 1; the rela- 

 tion of the total length of the stalk of the antennule to its width is 

 4.8 to 5; the stylocerite reaches the distal third of the median article; 

 the external flagellum bifurcates only at the tenth article. 



