FISHERY BULLETIN: VOL. 71 NO. 4 



Geogra'phical distribution: Verified localities 

 (Figure 17) suggests a broadly tropical distri- 

 bution restricted to the Indian and Pacific 

 Oceans. A deliberate search among several 

 hundred plankton samples from Atlantic Ocean 

 localities scattered over the lower latitudes 

 failed to yield a single specimen of atteuuatus 

 s.s. The species is widespread in tropical lati- 

 tudes of the Indo-Pacific but appears to be most 

 abundant immediately downstream of eutrophic 

 regions along the equator. 



Reference: Three lots of reference specimens 

 deposited in the U.S. National Museum 

 (USNM). 



2 99. USNM 143848. Cruise Dodo VI, stn 

 49, 1-m net. 0-200 m wire out (MWO); 20 Aug. 

 1964, 1445-1500 h; 10°19'N, 53°11'E. 



3 99. USNM 143849. Cruise Dodo VI, stn 47, 

 1-m net, 0-200 MWO; 19 Aug. 1964. 1825-1840 

 h; 8°53'N,53°09'E. 



1 9. USNM 143850. Cruise Scot (T058-1), 

 stn 35, 1-m net, surface; 7 May 1958, 0343 h; 

 9°45'N, 96°04'W. 



Remarks: Dana's (1849, p. 18, 19) first local- 

 ity given for attejiuatus is from the vicinity of 

 the Kingsmill ( = Gilbert) Islands in the western 

 Pacific (13 April 1841). Other U.S. Exploring 

 Expedition localities include the China Sea at 

 about lat. 5° to 10 °N (15 February 1842) and 

 the Sulu Sea (2 February and 2 March 1842). 

 All of these localities lie in Indo-Pacific tropical 

 waters, the biogeographical zone and the geo- 

 graphical region that yielded most of the records 

 of atteinmtiis s.s. Moreover, Dana's figures 

 (1853, Figure 2d, e) of utteiinatui^, while crude 

 emphasize a short wide-angled forehead charac- 

 teristic of the tropical population. 



Vervoort (1946) noted two morphological 

 kinds of atteuuatus s.l. in SiieUius collections, 

 and his illustration (Figure 7c) probably refers 

 to attenautus s.s. 



Sewell's (1947) description of pseudattenuatus 

 shows a pattern of integu mental organs ascrib- 

 able to the tropical species attenuatus s.s. His 

 illustration of atteuuatus (1947, Text Figure 

 7B) appears on the basis of an incomplete 

 account of integumental organs and the fore- 

 head to be referrable to sewelli described below. 



aor 



7.0 



E 

 E 



6.0 



5.0 



4.0 



100 



^ langae 



<| parki 



^ attenuatus 



() sewelli, Indo-Pacific samplei 



4 sewelli, Atlantic sample 







^) 



110 



120 



130 



PERFORATION NUMBER 



Figure 16. — The attenuatus group of Eucalanus. Perfora- 

 tion number plotted against total length (TL) in adult 

 females comprising the pooled samples. 



Brodsky's (1962) description of pseudattefiu 

 atus may be based on attenuatus s.s., but the 

 figures fail to provide adequate details of the 

 forehead and the absence of information on dor- 

 sal integumental organs on ThIII and ThIV 

 leave the issue open. 



Eucalanus sewelli, n. sp. 



(Figures Ir, 15c, 18b-d, o, r) 



E. attenuatus: Vervoort 1946, p. 95-103 (pars), 

 Figs. 7d-f; Sewell, 1947, p. 39, Text-fig. 7B; 

 Brodsky 1962, p. 113, Fig. 14. 



992 



