20 4 DISCOVERY REPORTS 



the chaetae in these two species. The only species with serrations on the shaft is P. serrata; P. longi- 

 cirrata has smooth shafts. Chamberlin (1919) and Fauvel (1923) appear to have followed Southern 

 in recording that P. longicirrata has a denticulated shaft without having specimens illustrating it. On 

 the other hand, Fauvel (1916), Monro (1936) and Stop-Bowitz (1948 and 1949) in reporting P. longi- 

 cirrata all made particular reference to the presence of smooth shafts on the compound chaetae. The 

 lack of denticulations was attributed either to inferior microscopic magnification, or regarded as 

 being only of varietal importance. When Gravier (1911a) first described P. viguieri, he assigned to it 

 characters which, compared with those of P. longicirrata, are due only to differences in growth (large 

 cirri, number of segments, extent of the nuchal organs) except for the shape of the chaetae. His 

 description of the chaetae is similar to mine above for P. longicirrata, but he was clearly influenced 

 by Southern's diagnosis and probably felt that because the shafts of the chaetae in his specimens were 

 smooth, they must be separated from a species which had denticulated shafts. Benham (1921 and 

 1929) assigned specimens to P. viguieri without considering P. longicirrata, which he probably over- 

 looked; some of this material is in the B.M.(N.H.) collections (Reg. no. 1928.2.29.14/18:20), and it 

 is identical with my Discovery material. 1 Treadwell (1943) and Uschakov (1952 and 1955) appear to 

 have followed Chamberlin (19 19) and Fauvel (1923), in describing specimens as P. viguieri. 



In submitting, therefore, that P. viguieri is a synonym of P. longicirrata, I have purposely not 

 considered the status of P. serrata. This species has been reported by Southern (1909) from off the 

 Irish Coast and by Fauvel (19 16) from the Azores and Monaco. It is clearly different from P. longi- 

 cirrata, but whether or not this difference warrants specific status depends on an examination of 

 many more specimens than are now available. 



General distribution. P. longicirrata is cosmopolitan, but exhibits important geographical and 

 seasonal patterns of distribution within the Antarctic and Sub-Antarctic Zones (see pp. 237-242). 



Genus Maupasia Viguier, 1886 



Prostomium with four antennae. Three pairs of tentacular cirri. Parapodia uniramous with dorsal 

 and ventral cirri, and compound chaetae only. Proboscis smooth. Anal cirri rudimentary. 



Type species. Maupasia caeca Viguier, 1886. 



Type locality. Bay of Algiers. 



Maupasia caeca Viguier, 1886 



Maupasia coeca Viguier, 1886, pp. 382-5, pi. 21, figs. 14-20. 



Maupasia caeca var. atlantica Southern, 1909, pp. 4-5, pi. 1. 



Maupasia caeca Ehlers, 1912, p. 15. 



Maupasia caeca Ehlers, 1913, p. 462. 



Maupasia caeca Fauvel, 1916, p. 63. 



Maupasia caeca Fauvel, 1923, pp. 190-1, fig. 71 a-d. 



Maupasia caeca Hardy and Gunther, 1935, p. 115. 



Maupasia coeca Wesenburg-Lund, 1939, pp. 19-20, fig. 15, chart 11. 



Description. This species measures up to 6 mm. long by 1 mm. wide across the bases of parapodia 

 and up to 3 mm. wide across the tips of chaetae; the number of chaetigers varies between fifteen and 

 eighteen. The small prostomium is approximately circular in shape, with two dorsal and two ventral 

 antennae, equal in length, on the outer anterior margins. Two pairs of long tentacular cirri are 

 situated immediately behind the prostomium on each successive segment, not clearly separated from 

 each other but distinctly marked off from the segment behind. Each pair of tentacular cirri have 



1 These specimens are from 'Terra Nova', Sts. 275 and 288 respectively, the specimen from St. 343 (B.M.(N.H.), Reg. 

 no. 1928.2.29. 19) is Maupasia caeca (see Benham, 1921). 



