82 University of California Publications in Zoology (VoL. 23 
Kry TO THE CALIFORNIA GENERA OF THE CRAGONIDAE 
I. Rostrum present. Eyes free. Dactyls of fourth and fifth pairs of feet long, 
acuminate, and more or less flattened. 
A. Rostrum short, more or less dorsally flattened. All five pairs of legs 
present. 
Crago, p. 82. 
B. Rostrum elongate; a laterally compressed, suberect spine. Second pair 
of legs wanting. 
II. Rostrum wanting. Eyes nearly concealed or hidden by carapace. Dactyls of 
fourth and fifth pairs of legs dilated, adapted for swimming. 
Nectocrangon, p. 102. 
Genus Crago Lamarck 
Rostrum very short and more or less dorsally flattened. Eyes free. Dactyls 
of fourth and fifth pairs of legs more or less flattened. 
KEY TO THE CALIFORNIA SPECIES OF CRAGO 
I. Gastric region not depressed below general level of the carapace. Antennal 
scale with very oblique inner margin and narrow extremity; spine 
exceeding blade except in C. nigricauda, in which it is variable, longer 
or shorter than the blade. 
A. Carapace without a median gastric spine. : ; 
stylirostris, p. 90. 
B. Carapace with one or more median spines. 
1. Carapace with one median spine. 
a. Sixth segment of abdomen sulcate beneath. 
i. Hand of first pair of feet very slender, four or more times 
as long as wide; dactylus when flexed almost longitudinal. 
Fifth abdominal segment not carinate. 
franciscorum, p. 92. 
ii. Hand of first pair of feet not slender, less than three and 
one-half times as long as wide; anterior margin against 
which dactylus closes usually more transverse than longi- 
tudinal, never forming an angle of less than 45° with 
lengthwise margin. 
a. Fifth segment of abdomen not carinate. Blade of anten- 
nal scale having its anterior margin more advanced at 
inner than at outer angle. Sixth abdominal segment 
with a large circular spot, characteristic only of this 
species, on either side at its posterior end. 
nigromaculata, p. 86. 
b. Fifth segment of abdomen furnished with a _ superior 
median carina. 
i. Antero-internal angle of antennal scale advanced, reach- 
ing nearly as far as or farther than the spine. 
Hands of first pair of feet little over twice as long 
as wide; anterior margin against which dactylus 
closes more nearly transverse than longitudinal. 
nigricauda, p. 84. 
Paracrangon, p. 103. 
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