THE NAUTILUS. 99 



lowing the nucleus have two ribs on centre, each rib bearing a node 

 which is equidistant from the foliations ; three continuous fin-like 

 varices continued from apex, which revolve in descending, edges of 

 varices dentate. Body whorl with about thirteen distant spiral raised 

 ribs, the two on the peripheiy bearing a node each between the folia- 

 tions. Aperture elongate-oval. Outer lip having internally seven 

 plications, inner lip smooth ; canal rather long, almost closed pos- 

 teriorly, widening anteriorly, and bent upwards. Canal of preced- 

 ing aperture persistent. Alt. 65 mm. ; diara. 33 mm. 



This elegant Pteronotus is described from the unique example be- 

 longing to the National Museum. Named in honor of its discoverer, 

 Mr. F. Burns, of the U. S. National Museum. 



Cerithium serratoides n, sp. PI. 4, fig. 5. 



Shell elongate; suture linear; whorls ornamented with transverse 

 ribs, which are moderate near the suture, but suddenly become 

 enlarged and spinous at the intersection of a spiral near the middle 

 of each whorl ; a couple of fine spiral lines occur between the spines 

 and preceding whorl ; also a single spiral line just below the suture. 

 Whorls slightly shouldered. 



Specimen figured has lost its apex and aperture, but is so evi- 

 dently a serrate Cerithium that I have concluded to describe it. 



Length of part figured is 36 mm. 



Type in National Museum. Example in my cabinet. 



Latirus indistinctus n. sp. PI. 4, fig. (i. 



Shell fusiform, whorls nine, rounded ; apical whorl smooth, the 

 remaining ones transversely ribbed, crossed by raised lines that on 

 the body whorl are alternately coarse and fine ; suture distinct, whorls 

 appressed to it anteriorly. Canal long, twisted strongly to the right 

 and then to the left. Striations continue to the end of canal. Ap- 

 erture oblong-oval, toothed posteriorly and shouldered anteriorly. 

 Outer lip striated internally; inner lip covered with a thin callus, 

 definitely delineated and running to end of canal. No teeth on the 

 inner lip, but some of the striations show through the callus. Alt. 

 42 mm. ; diam. 14 mm. 



This handsome species is strongly Fusoid in appearance, and does 

 not possess plications on the inner lip like most of the genus, but it 

 evidently belongs there from its other characters. 



Type in the National Museum, One example in my collection. 



