no. 1404. PARASITIC COPEPODS—CALIGID.E— WILSON. 639 



The first swimming legs of this new species are short and thick, 

 the basal joint with a short spine at the distal end, the terminal joint 

 with the usual spines and setae. 



The second and third legs are slender but otherwise like those in 

 other species. The fourth legs are large and stout, four-jointed, the 

 basal joint somewhat swollen and as long as the other three, with a 

 plumose seta at its distal end on the outer margin. The second joint 

 has a very short and strongly curved claw at its tip; the third joint 

 has a much longer one, while the three terminal claws are still longer 

 and increase in size from without inwards. The last four claws are 

 close together and they all have serrate flanges along their outer 

 margins. At the base of each of the claws on the dorsal surface is a 

 large semicircular lamina made up of radiating thread-like spines, 

 connected by a membrane. The tips of the spines project beyond 

 the edge of the membrane, giving it a serrated appearance. The fifth 

 legs are small and are not visible dorsally. 



Total length 4.8 mm. Length of carapace 2.7 mm.; width of same 

 2.4 mm.; length of genital segment 1.6 mm.; length of abdomen 0.3 

 mm.; length of egg cases 1.7 mm.; twenty eggs in each case. 



Color, a dark-brownish yellow, without pigment spots. 



(hifarcatus, forked or divided into two branches, i. e., with a double 

 furca.) 



There is but a single lot containing two females of this new species, 

 and the male is unknown. The} T were taken from one of the common 

 flounders of the Pacific coast, Psettichtkys tnelanostictus, in San Fran-* 

 cisco Bay, California. 



This species is distinguished from all others by the peculiar structure 

 of the furca, as already noted. The wide separation of the branches of 

 the second maxilla? is another distinguishing characteristic, the sinus 

 between the branches being very much broader than in any known 

 species. The fourth legs furnish a third character in the prominent 

 spiny lamellae at the bases of the claws. So far as known these are 

 not present in any other species of the genus. There is but a single 

 female with egg cases from which to diagnose the species, but every- 

 thing about them seems to point to a very small number of eggs. The 

 thickness of the eggs for any species does not vary appreciably, 

 whether many or few have been extruded, and in this species they are 

 much thicker than ordinary. In fact, the only other species which 

 approaches it in this respect is dissunulatus, which has just been 

 described. 



