OF CONCHOLOGY. 



131 



The central spiral lobe of the brachia, prominent in tlie Euro- 

 pean species, seemed to be nearly M^anting in the Australian 

 shell. The fringes in the former were nearly twice as long, the 

 individual filaments much more slender, and five or six times as 

 numerous as in the latter. 



The range thus indicated is extraordinary, and much more 

 remarkable than the discovery of Indo-Pacific species in Japan 

 by Arthur Adams ; still the recent deep sea dredgings by Eng- 

 lish and American naturalists overturn many of our former no- 

 tions in regard to the distribution of marine animals, and we 

 may expect to find the range of low forms, such as the Brachio- 

 poda, greatly increased by further researches. 



Genus MAGAS, Sby. 



3Iagas, Sby., Min. Con. vol. ii, p. 39, 1818. Day., Int. Br. 

 ' Brach. p. 70, 1851. Mon. ^Cret. Brach. p. 19. Ann. 



Nat. Hist. 1852, p. 371. D'Orb., Bal. Fran. Ter. Cret. 



1847, iv, p. 54. Gray, B. M. Cat. 1853, p. 98. Woodw., 



Rec. and Foss. shells, p. 217. H. and A. Adams, Gen. 



Rec. Moll, ii, p. 577. Chenu, Man. de Conchyl. ii, p. 



207. Rve., Conch. Icon. pi. 8. Journ. de Conchyl. 



1861, p. 130, King, Perm. Foss. p. 81. 

 Orthis sp. De Koninck (not Dalman). 

 Rhyncliora, Dalman, 1827 {Ii. spathidata) part. 



Shell with a prominent septum in the haemal valve, to which 

 the haemal processes of the loop are attached by their sides be- 

 fore being reflected. 



(In Terehratella the hasmal processes are attached to the sep- 

 tum by septal processes; in the present genus no septal pro- 

 cesses intervene, but the attachment is of the haemal processes 

 themselves directly to the septum by their inner edges.) 



Type Magas jmniila, Sby. 



Subgenus Magas. 

 Reflected portion of the loop incomplete in the adult. 







■I 



h 



Fig 15. 



Fig. 15 a, b. Mar/as Pumila, j nat. size, o, crura : ^, incomplete loop 

 septum. 



