160 J. WILFRID JACKSON ON 



Dallininge and Magellaninas, were geographically separated into two provinces, one 

 (Dallininse) being restricted to boreal, the other (Magellaninse) to austral seas 

 (ScHUCHERT, in Zittel, 1900, p. 329). 



It can now be shown that the sub-family Dallininse is well represented in the 

 austral region. 



This discovery is of still further interest as being highly confirmatory of BALL'S 

 observations when first describing this and two other species of Macandrevia from the 

 Gulf of Panama (BALL, 1895, p. 721). 



He remarks : " As regards the partly austral species about to be described, since 

 there is no means of deciding whether their development agrees with those forms refer- 

 able to Magellaninse or not, and as the adult shells exhibit no characters which could 

 not be regarded as diagnostic of a genus different from Eudesia* I feel obliged for the 

 present to refer them to that group. It may be observed that there is nothing to 

 prevent the free migration of northern forms into the South Pacific along the coast of the 

 Americas. The writer has already the evidence to show that several species, in deep 

 water, do extend from Bering Sea south to the vicinity of the Galapagos Islands and, 

 in the case of one species, Solemya johnsoni, Dall, more than a thousand miles further 

 south ; with the known great range of many brachiopods, there would be no apparent 

 reason why species of the Panamic region, for instance, belonging to the northern type 

 of development, should not extend their range southward, if opportunity arose. 1 

 regard it then as quite likely that the species I refer to may be Macandrevian in their 

 development as well as in their adult state, though, for the mass of characteristically 

 austral species, the reverse might be the case." 



The prescience of this eminent American author has thus been amply justified. 



Macandrevia diamantina was originally described from two specimens obtained in 

 deep water, 1175 fathoms, mud, Gulf of Panama; bottom temperature 36'8 F., and 

 was again met with later in 2222 fathoms, mud, off Sechura Point, Northern Peru ; 

 temperature 35 '2 F. 



The discovery, therefore, of this species in deep and cold water off the coast of the 

 Antarctic continent is highly interesting as showing a very considerable range 

 southward. 



Furthermore, it forms a connecting link in the distribution of the genus Macan- 

 drevia, which now ranges from the North Atlantic (M. cranium), Davis Strait 

 (M. fenem), via the Gulf of Panama (three species, viz. M. americana, M. cranieUa, 

 and M. diamantina), Peru (M. diamantina}, West Patagonian coast (M. americana), 

 Coats Land (M. diamantina), to Kaiser Wilhelmland II., Antarctica (M. van//i>(fci,i). 



Though the distance between the recorded stations for M. diamantina appears to be 

 so great, it is not at all improbable that it will ultimately be met with in other 

 stations off the long South American coast as further dredgings are carried out in that 

 area. Macandrevia americana, one of the Panamic species, has already been found 



* DALL regarded Macandrevia as a sub-genus of Eudesia. 



(ROY. 80C. EDIN. TRANS., VOL. XLVIII., 382.) 



