104 University of California Publications in Zoology [Vol. 23 



immature specimen, from a depth of 38 to 45 fathoms, off Santa Bosa Island 

 ("Albatross" station 4431), and one, a male from 46 to 56 fathoms, in Monterey 

 Bay ("Albatross" station 4551). Still another California specimen is contained 

 in the collection of the Scripps Institution; it was taken July 11, 1905, in 110 

 fathoms, off La Jolla (haul 998). 



Suborder Bjeptantia 



Key to the Teibes of the Eeptantia 



I. Third pair of legs like the first. Abdomen macrurous, straight, symmetrical, 

 well armored, with good pleura and strong tail-fan, lobes of first seg- 

 ment clipping the carapace. 



A. Eostrum small or wanting, third pair of legs simple and subcylindrical, 



carapace fused at sides to the epistome. Exopodites of last pair 

 of abdominal appendages without sharp suture. (Not known north 

 of San Luis Obispo.) 



Palinura, p. 105. 



B. Eostrum of good size; third legs chelate. Carapace free from the 



epistome. Exopodites of last pair of abdominal appendages divided 

 by a suture. (Except for the crayfishes, fresh-water forms, not dealt 

 with in this paper, not found in California waters.) 



Astacura. 

 II. Third pair of legs unlike the first, abdomen rarely macrurous. 



A. Abdomen fairly large, ano-murous; reduced 'in some of its features, 



but showing clear traces of some function other than that of repro- 

 duction, and almost always carrying biramous limbs on the sixth 

 segment. Tail-fan usually present, uropods biramous, absent only 

 in the Lithodidae. Carapace not fused with epistome. Antennae 

 situated external to the eye, with long flagellum, often with mov- 

 able antennal scale. Last thoracic sternum free, its legs always 

 differing clearly from the third pair in size and position and nearly 

 always in size and shape. 



Anomura, p. 109. 



B. Abdomen comparatively small, brachyurous ; small, straight, symmetri- 



cal, bent under the thorax, showing no traces of other function than 

 reproduction, and without biramous limbs on the sixth segment. 

 Tail-fan not developed, uropods rarely present, never biramous, only 

 in the Dromiidae are they present and then only in a rudimentary 

 condition. Carapace fused with epistome at sides and nearly always 

 in the middle. Antennae situated internal to the eye, seldom with 

 long flagella, and never with a movable scale. Last thoracic sternum 

 fused with the rest, its legs often like the others. 



Brachyura, p. 182. 



