.THE NAUTILUS. 87 



This form is much more slender than P. chemnitzoides Fbs., which 

 is well represented by the figures 6a, 6b, plate IX, Proc. Zool. Soc. 

 London, 1850. Aside from the differences in color and sculpture, 

 the surface of Forbes's species is dull in fresh, unrubbed, perfect 

 specimens ; the ribs in the latter species are comparatively sharp, 

 thread-like, regular, and somewhat distant, the interspaces being 

 perceptibly wider than the ribs are thick. 



Two perfect examples, U. S. Steamer Albatross. The U. S. 

 National Museum also contains specimen collected by Dr. S. Habel 

 several years ago, as well as examples of Forbes' species. 



Chatham Island, April 4th, 1888. 



A brief description of the foregoing was included in Mr. Ball's 

 paper, " On some types new to the fauna of the Galapagos Islands " 

 in The Nautilus, January, 1892, which also contained descriptions 

 of Helicina (Idesa) nesiotica, Leptinaria Ghathamensis, Zonites 

 {Hyalinia) Baueri. Reibisch^ who has recently published a paper 

 on the Fauna of the Galapagos Islands, was probably not aware of 

 Dall's article, as he has apparently redescribed the same forms. 

 Orchidium Leslie! Stearns. 



Form rounded ovate, nearly as broad as long. Dorsum coria- 

 ceous, nearly black, shiny, closely irregularly reticulated, with finely 

 incised lineation, and otherwise characterized by somewhat distant 

 flatly rounded papilL^. Underside, dingy yellowish white ; margin 

 of mantle wide, nearly smooth ; edge of same simple. Anal opening 

 posterior, near edge of mantle and somewhat produced. Respiratory 

 orifice smaller, in median line with and in front of anus. Sexual 

 orifice anterior on the right side, under the edge of the large oval 

 hood or collar. Labial palpi thin, largely expanded. 



Charles Island, April 8th, one example; Albemarle Island, April 

 10th, 1888, two specimens between tide-marks. United States 

 Steamer Albatross. 



Littorina (Tectarius) Galapagiensis Stearns. 



Shell small, rather solid, ovate-conic, angulated in outline ; five to 

 six and a half whorls. Whorls covered with obtusely rounded 

 rather coarse nodules ; of these the peripheral series is the strongest, 

 the next preceding less prominent, while the other girdles of nodes 

 are less conspicuous. The peripheral is closely followed by a 



^ Die Concholiologische Fauna der Galapagos-Inseln, von Paul Reibisch, Ges 

 Isis in Dresden, 1892, Abh. 3, 20, pp. 2 plates. 



