Io2 THE NAUTILUS. 



stai ting points for numerous subsequently developed genera, are 

 usually notable for their tendency to vary and interchange charac- 

 ters. In the present case, perhaps, the very general habit of com- 

 mensalim or parasitism, has produced degeneration, accompanied by 

 a revival of atavistic primary characters." 



Other introductory remarks are followed by a list of species from 

 the east and west coasts of North America, with synonymy and dis- 

 tribution. From the east coast there are recorded 13 genera, 34 

 species and one variety ; from the west coast 12 genera, 33 species 

 are listed. 



A list of the tertiary species of ihe United States is also given, 

 containing 73 species, divided among 13 genera, followed by "de- 

 scriptions of new species and remarks on others imperfectly known." 

 18 new recent species are described, all of the new species are in- 

 cluded in preceding lists. On plate 87 is shown a crab (Gebia pu- 

 yctensis, Dana), with Erycina rtit/i'fera, Carp., attached by its bys- 

 sus to the underside of the abdomen of the crab. C. W. J. 



THE MOLLUSK FAUNA OF THE PRIBILOF ISLANDS. By Wm. 

 H. Dall. (Extracted from The Seals and Fur-Seal Islands of the 

 North Pacitic Ocean, Ft. Ill, pp. 539-546, 1899.) 



A very interesting paper on the geographical distribution of species 

 and the physical characteristics of the region. The faunal summary 

 gives a total of 86 forms. Only three land shells are known from the 

 group : Succinea clirysis, Vitrina exilis and Pupa decora var.? A 

 fauual summary of the Commander Islands given for comparison, 

 shows a total of 74 species from those islands, including six land and 

 three fresh-water forms : Limax hyperboreus, V. exilis, H. radiutnltt, 

 Conn his fulnts, Patnla ruderata var. pauper, P. decora, Limncea orata, 

 L. humilis and Pisidium aquilaterale. Fossil mollusks were found 

 only on St. Paul Island. 



DESCRIPTION OF A NEW GENUS, AUSTROSAREPTA, AND NOTES 



ON OTHER MOLLUSCA FROM NEW SOUTH WALES. By Charles 



Hedley. (Proc. Linn. Soc. N. S. W., pt. 3, pp. 429-434, Dec. 1899.) 

 Following Dr. Dall's classification, Mr. Hedley places this interesting 

 genus in the subfamily Sareptirxz ; the type is a new species A- picta. 

 A new species, Tewostoma xtarkeyce, is described and figured. Sol en 

 sluaull Gray, Nerifula Jucida, Cassis nana T. Woods, Cantharus 

 waterhousia lira/.., are also figured -C. W. J. 



