ISOPODS OF NORTH AMERICA. 



387 



The abdomen is composed of a single segment, with a suture line on 

 either side at the base. The segment becomes somewhat narrower 

 toward the extremity, which has a broad but shallow excavation or 

 notch. 



The legs are all similar in structure. 



SYNIDOTEA HARFORDI Benedict. 



Idotea marmorata HARFORD, Proc. Cal. Acad. Sci., VII, 1877, p. 117. 



Synidotea harfordi BENEDICT, Proc. Acad. Nat. Sci. Phila., 1897, p. 402. RICH- 

 ARDSON, Proc. U. S. Nat. Mus., XXI, 1899, p. 849; Ann. Mag. Nat. Hist. 

 (7), IV, 1899, p. 269. 



Localities. Magdalena Bay, Lower Cali- 

 fornia (Benedict); San Diego Bay, Cali- 

 fornia. 



Depth. 6f fathoms. 

 Body ovate, two and two-thirds times 

 longer than wide, 6 mm. : 16 mm. Length 

 of abdomen 6 mm. 



Front of head without any emargination 

 or median notch, frontal margin straight. 

 Head slightly narrower at its anterior end 

 than at its posterior end. Eyes large and 

 round, composite in structure, and placed 

 in the middle of the head at the extreme 

 lateral margins. First pair 

 of antennae with the basal 

 article short, not dilated; the 

 second and third subequal, 

 and each only a little longer 



than the first; the fourth article is twice as long as 

 the third. The first pair of antennae extend to the end 

 of the third article of the peduncle of the second pair 

 of antennae. The basal article of the second antennae 

 is short; the second article is twice as long as the first; 

 the third is a little longer than the second; the fourth 

 is twice as long as the third; the fifth is one and a 

 half times longer than the fourth. The flagellum con- 

 sists of thirty -one articles. When retracted the second 

 antennae extend to the middle of the seventh thoracic segment. The 

 maxilliped has a palp of three articles. 



The first four segments of the thorax are Ipnger than the last three. 

 All the epimera of all the segments are firmly united with the seg- 

 ments. The lateral margins of the segments are straight. 



The abdomen is composed of only one segment, with lateral sutures 

 at the base, indicating another partly coalesced segment. The poste- 



FIG. 427. SYNIDOTEA HARFORDI 

 (AFTER BENEDICT), x 3|. 



FIG. 428. SYNIDO- 

 TEA HARFORDI. 

 MAXILLIPED. x 

 27*. 



