1100 



CRUSTACEA. 



nearly 130°. The external seta of the stylets proceeds from near the 

 middle of the stylet, rather nearer the base than apex. The other 

 setae were mutilated, and those of the antennae also were often so. 

 The plumes either side of the body were as long as the breadth of the 

 body. 



The position of the antennae in figure 4 a' may be more correct (or, 

 at least, more common) than that in 4 a. 



Oithona plumifera, Baird, Zoologist, 1843. 



Scribella scriba, Dana, Proc. Amer. Acad. Sci., ii. 20. 



OlTHONA ABBREVIATA. 



Antennae anticce lath divaricatce, 7-articidatoe, articulis duobus ultimis 

 brevibus, tertio quarto quintoque subaequis. Seto3 external pedium 

 biremium obsoletm (an distinctio sexus?). Abdomen 5-articidatum ; 

 setis basalibus dimidio abdominis valde brevioribus, submquis, curvatis. 

 Styli caudales paulum divaricati; setd externa joerbrevi. 



Anterior antennae widely divaricate, much shorter than the body, 

 seven-jointed, last two joints very short, second moderately 

 short, third, fourth, and fifth subequal; setae less than half the 

 length of the antenna. External seta of the natatories wanting. 

 Abdomen five-jointed; first segment usually nearly half the second, 

 and having on either side two curved setae, subequal, and of mode- 

 rate length. Caudal stylets sparingly divergent, outer seta very 

 short; second seta slightly longer than abdomen; third more than 

 half same length. 



Plate 76, fig. 5 a, animal, enlarged ; b, maxilliped. 



Collected abundantly, off Patagonia, in the Pacific, January 21, 

 1839, latitude 40° south, longitude 55° 30' west; also, April 21, 1840, 

 one hundred miles southeast of Tonga; also, July 7, 1841, latitude 

 44° 15' north, longitude 153° west. 



Length, one-twenty-fourth of an inch. Colourless. 

 A large number of specimens were taken and examined, but in 

 none were the setae entire. If the absence of the external setae of the 



