21<> ATI Ki A. li I S' IT KS. 



cles were extended radially from the head, soincwliat like those 

 of a sea anemone; but each pair liad its definite and different 

 direction, which was constantly maintained ; thus one pair of 

 tentacles was held pointing directly downwards, two other pairs. 

 situate just before and behind the eyes, were held projecting 

 obliquely outwards and forwards, and backwards respect ivelv. as 

 if to protect the organs of sight." 



N. STK.XOMIMIALIS. So\vl). PL 90, fig. ">0 ( .l. 



Shell like N. /'ni/>///i'*. but very narrowly umbilicated. 



Eastern A rch ipelayo. 



\ scarcely think this deserves to lie separated from A'. Ptnn- 

 /H'iinx: the very narrow umbilicus is exposed simply because the 

 callous deposit has not spread sufficiently to cover it ; there is 

 no excavation around the umbilical region, as in the following 

 species. 



N. .MACUOMIMTALUS, Sowb. PL 99. fig. .Mo. 



Umbilical region excavated, but with rounded margin; umbili- 

 cus wide, exposing the whorls. 



New Caledonia, etc. 

 X. r.MBlUCATi's. Lister. PL 90. fig. f)11. 



Surface smooth to spirally striate; umbilieal region wide. 

 angularly excavated, umbilicus wide, showing all the whorls. 



Solomon Islands, New Ireland, etc. 



The stri;e are not constant; I have therefore reunited with 

 this species N. xcrobiculatus of Dillwyu and Uould and ,V. />er- 

 foratus, Conrad. 



Subgenus Aturia, Bronn. 



Sutures of septa with a deep lateral lobe; siphuucle on the 

 concave or inner side of the shell, large, continuous, like a suc- 

 cession of funneU. 



Lour species. Eocene. N. America ; tin /<>/><; India. 

 A. /IOZAC, Sby. PL 98, figs. 502, 503 a. Eocene. //////.>/,. 



Discites, Mc('<.v. 



Whorls all exposed ; last chamber sometimes produ<-ed. 

 Five species. L. Silurian t'arb. 



Mosely, Notes by a Naturalist on the Challenger, ~!>i!. 



