288 bulletin: museum of comparative zoology. 



For distributional purposes we may divide the stations into three 

 classes : — first those where E. compressa was twice as numerous as 

 E. hispinosa, at one level at least, and about equal to it in numbers at 

 the other; second, the reverse; and thirdly stations where the two 

 were either nearly equal in numbers, or where one greatly predomi- 

 nated at one, the other at another depth. On this basis E. compressa 

 predominated in the southwest part of the Gulf of Maine, and locally 

 in its northeast corner (Stations 10246, 10248), on the northeast edge 

 of Georges Bank (Station 10226), over the outer part of the shelf south 

 of Shelbume, Xova Scotia; and probably all along the continental 

 slope (Stations 10218, 10220, 10233, 10261). E. bispinosa outnum- 

 bered E. compressa in the eastern part of the Gulf, in the Northern 

 Channel, on Brown's Bank, locally off Halifax (Station 10237), and 

 over the southern part of Georges Bank. 



In 1915 E. compressa was the more numerous of the two in the Gulf 

 in May and June; but in the latter month E. bispinosa predominated 

 over the outer part of the shelf off Shelbume (Station 10294) as well 

 as on Brown's Bank (Station 10296). In August E. bispinosa pre- 

 dominated in the Western and Eastern Basins (Stations 10307, 10310) 

 and on German Bank (Station 10311), while it outnumbered E. com- 

 pressa locally off Marthas Vineyard (Stations 10331-10333), ofiF Cape 

 Cod and in Massachusetts Bay in October (Stations 10336, 10337). 

 These records suggest that while E. compressa is a permanent and 

 characteristic inhabitant of the Gulf, E. bispinosa is absent, or at 

 least rare, there in spring, appearing in summer, when it may locally 

 outnumber E. compressa, particularly in the eastern half of the Gulf. 

 But it is very rarely as numerous as E. compressa in the coast water 

 of the western side of the Gulf, and that only in autumn, as just noted, 

 and in winter (1914b, p. 410). 



In the coast waters off Xova Scotia E. bispinosa is faunistically 

 more important, usually equalling if not outnumbering E. comjyressa, 

 particularly over the outer part of the shelf. We have always found 

 it the predominant member of the pair in the shallow waters south of 

 Marthas Vineyard, and on the southern part of Georges Bank. In the 

 coast water east of Cape Cod, E. bispinosa is apparently the more 

 oceanic of the two. But the difference between the two, in this respect, 

 is one of relative abundance only, for they occur together in most of 

 our hauls, and it is difficult to correlate the predominance of one, or 

 the other with hydrography, or with depth, though E. bispinosa has 

 more often outnumbered E. comjyressa in deep, than in shallow hauls, 

 especially at localities where both species are abundant. 



