64 University of California Publications. [Zoology 



It will be seen that these animals occurred in two collections ; 

 in one of these (1030) E. calif ornica was found and in the other 

 E. ■propinqiia. It is difficnlt to say with any certainty whether 

 the males belong to one species or the other, and for that reason, 

 and in the absence of structures pointing one way or the other, I 

 have kept the sexes in separate species. Possibly immature forms 

 will be found later that will make clear the true relations. 



Euchaeta tonsa Giesbrecht. 



PI. 9, fig. 10; pi. 10, fig. 32. 



Euchaeta tonsa, Giesbrecht ('95), p. 251, pi. 3, figs. 9, 10; ('98),. 

 p. 40. 



Female: The species lies in the group with norvegica, flava, 

 and calif or nica, but is distinct from them in the absence of the 

 tufts of hair on the last thoracic segments ; the segment instead 

 of being rounded laterally ends in a small tooth (PI. 10, tig. 32). 

 The frontal eminence (PI. 9, fig. 10) is rather high and slightly 

 protruding. The shape of the genital segment is different from 

 that in any of the allied species ; the eminence is prominent and 

 lies far back in the segment, so that its posterior l)order almost 

 coincides with that of the segment, and the hirsute transverse 

 line behind the eminence is lacking. The first lobe on the outer 

 border of the maxilla has nine bristles {norvegica nine, flava five, 

 calif ornica seven). The terminal joint of the outer ramus of the 

 second foot is similar to that in the other species ; the middle 

 bristle on the outer margin reaches beyond the base of the third. 



Length: Female, 6.1 mm. 



Coloration : Body rather opaque, without pigment. The dis- 

 tal bristles of the posterior maxilliped and all those of the ante- 

 rior are a magenta red. 



Occurrence : Twelve females. Coll. 1030. 



Genus Scolecithrix Brady. 



Scolecithrix, Brady ('83), p. 56. 



Scolecithrix, Giesbrecht ('92), p. 56, 265, 764; ('98), p. 41. 



Scaphocalanus, Sars, (:00), p. 35. 



Scolecithrix, Esterly (:05), p. 163. 



The genus Scolecithrix of Giesbrecht contains a large number 

 of species, all of w^hich have been retained in the genus by Gies- 



