CALIFORNIA STALK-EYED CRUSTACEA. 169 



outer oue setose on one side except near the base. Peduncle of the 

 antenna? armed with short, strong spines; flagellum spinulous, compressed 

 at the base, and exceeding the body in length. Epistome with the trun- 

 cated anterior end armed with five or more spines, the median and outer- 

 most spines the largest. Ambulatory legs smooth, pubescent distally, 

 the coxse of the last pair armed with a pair of spines. Abdominal seg- 

 ments furnished wnth a pair of transverse dorsal setose sulci which do not 

 meet in the middle line except on the sixth segment. Telson spinulous 

 at the base. 



Southern California to Mexico. This is the common 

 '' spiny lobster " of the markets. 



P. gracilis Streets, which has been united with inter- 

 ruptus, differs from the latter, according to Ortmann 

 who has examined the types of both species, in having 

 no transverse sulci on the segments of the abdomen. 



Subtribe CARIDEA. 



Body generally laterally compressed, the integument usually of flexible 

 corneous texture. Carapace not united to the epistome. Antennules with 

 a three-jointed peduncle, usually furnished with an external basal spine 

 and two or three flagella. Antennal scale generally well developed. Ex- 

 ternal maxillipeds generally pediform. Either, both, or neither of the 

 first two pairs of pereopods may be chelate, the three posterior pairs 

 always simple. Abdomen long, the sides produced downwards. Caudal 

 fin well developed. Gills phyllobranchiate. 



The Caridea are divided by Bate into four groups: — 



1. Crangoninea, with the characters of the single family Crangonidae. 



2. Polycarpinea: Carpus of the second pereopods annulated, or divided 



into secondary joints. Four families, Nikidae, Alpheidae, Hippo- 

 lytidae, Pandalidse. 



3. Monocarpinea: Carpus of second pereopods undivided. This group 



is divided by Bate into eleven families, only two of which are 

 represented in our limits, the Atyidae and the Palasmonidse. 



4. Haplopodinea: All of the thoracic legs similar. Single family, Hec- 



tarthropidsB. 





