156 University of CaJifornia Puhlications in Zoologij. [Vol.8 



From these data Ave may be sure that this species is strictly 

 epiplanktonic. It can not be regarded as typical of the San 

 Diego region, and since it occurs elsewhere on the surface when 

 the temperature of the water is as high as 34°, it seems probable 

 that it was carried into this region by currents from the more 

 tropical seas. We have, however, found it to occur in midwinter 

 when the temperature of the water was as low as 15?5, which, 

 on the above supposition, makes its distribution decidedly 

 puzzling. 



Distribuiion of S. neglect a 



This species, like 8. enflata, can scarcely be considered typical 

 of this region. It seems to be confined strictly to the surface, 

 for it was not obtained in either open vertical nets or horizontal 

 or vertical closing nets. Furthermore, of 127 specimens ob- 

 tained, all but five were taken in three hauls made during 

 February and April, 1905. Like ^'. en/iata, the species is typical 

 of the epiplankton of tropical seas, and its occurrence in the 

 region of San Diego during the winter when the temperature 

 of the water was 15?5 is likewise puzzlinji'. Were it not for the 

 low temperature noted, I should believe the species was carried 

 here by currents from the tropics. It is possible, of course, that 

 this species, as well as S. enflata, normally occurs here during 

 the -winter months and that it was not obtained in greater 

 numbers because practically no winter collections were made. 

 This, however, seems hardly probable. Our data warrant but 

 one conclusion, namely: S. neglecta, when it occurs at all in this 

 region, is confined to the upper epiplankton. 



Distribution of Spadella draco 



But one specimen was obtained, and that one in surface haul 

 411. Like S. enflata and S. neglecta, this species occurs typically 

 in the warmer water of the more tropical seas, and the reason 

 why it occurred in this region remains obscure. 



Distribution of Eukrohnia hamata 



Of 61 specimens obtained, six were taken in horizontal closing 

 nets below 100 fathoms, 16 in vertical closing nets below 25 



