MOI/LTJSCA OF THE ' CHALLENGES ' EXPEDITION. 407 



the sinus-scars, is perfectly preserved. This and the proportion 

 and form of the successive whorls are similar, though the line of 

 keel lies a little higher, the shoulder is squarer and shorter, while 

 the line from the keel to the suture is longer. "Were the loca- 

 lities of the two less distant and dissimilar, I would not hesitate. 

 Still the depth at which they live may secure similar conditions 

 for the species even from 35° N. to 37° S. ; and in any case I do 

 not feel able to part the specimens. 



In its expressed keel this very remarkable shell recalls the 

 young of P. tomata, Dillw., or of P. circinata, Dall. In form it is 

 slightly like P. spirata, Lam., or P. oiesa, Eeeve. The resem- 

 blance most striking of all, however, both in form and sculpture, 

 is one to which my attention was kindly drawn by Dr. H. Wood- 

 ward — that, viz., to P. catapJiracta, Brocchi, a fossil from the 

 Upper Miocene of the Vienna basin and Northern Italy (Brocchi, 

 ii. 221, no. 52, viii. 16, Lam. ix. p. 367, and Philippi, Enum. 

 Moll. Sicil. i. p. 199, ii. p. 171). Compared with that species, 

 this New-Zealand form is slimmer, the angulation of the whorls is 

 less, but the keel on the angulation is more prominent though 

 less nodulous and much lower placed, and the sinus is more 

 remote from the suture and is sharper. 



15. PlefeotOMA (GtENOTA) ATEACTOIDES, n. sp. (aTpaKToeidrjs, 

 spindle-shaped.) 



St. 210. January 25, 1875. Lat. 9° 26' K, long. 123° 45' E. 

 .Philippines. 375 fms. Mud. Bottom temperature 54 0, 1. 



Shell. — Fusiform, biconical, very slightly and bluntly angu- 

 lated, with a scarcely convex base, elongated into a largish, slightly 

 reverted, rather equal-sided snout. Sculpture. Longitudinals — 

 there are no ribs ; but the close-set, hair-like lines of growth, at 

 nearly regular intervals over the whole surface, rise into thread- 

 like folds which score the shell rather markedly. Spirals — near 

 the bottom of each whorl there is a slight keel on the line of the 

 old sinus-scars ; it includes two, bluntly rounded, close-set threads, 

 which are crenulated by a series of small squarish tubercles which, 

 being arranged in pairs, one on each thread and placed one above 

 the other, form short little bars ; they are parted by furrows 

 broader than they. There are about forty of these bars on the 

 last whorl, becoming more irregular towards the mouth : on the 

 penultimate whorl there are about fifty ; but they again diminish 

 in number on the upper whorls. Answering to these is another 



