REPOKT ON THE GASTEROPODA. 599 



February 10, 1873. Tenerife, Canaries. 70 fathoms. 



Habitat. — From North America (Gould), Spitzbergen and the Sea of Okhotsk 

 (Jeffreys), to the Mediterranean (Weinkauff, but queried by Monterosato), Madeira and 

 the Selvagens Islands (Watson), and the Canaries (Jeffreys). 



Fossil. — From the Pleistocene beds of Norway (Sars), Scotland, and England 

 (Jeffreys). 



23. Rissoa (Onoba) watsoni, Schwartz. 



Rissoa watsoni, Schwartz v. Mohrenstern, M.S. 



„ „ Watson, Madeiran Rissoae, Proc. Zool. Soc. Lond., 1873, p. 375, pi. xxxv. fig. 11. 



,, „ Reeve, Conch. Icon., voL xx. pi. xii. fig. 112. 



,, „ Weinkauff, Conch. Cab. (ed. Kiister), p. 174, sp. 89, pi. xxii. figs. 10, 11. 



February 10, 1873. Tenerife, Canaries. 70 fathoms. 

 Habitat. — Madeira (Watson). 



The Marquis of Monterosato was in error in identifying Rissoa simulans, Monterosato, as this 

 species, but he is perhaps right in his later identification of another closely allied species as Missoa 

 watsoni (Enumeraz., p. 25) ; however, as I have not seen the Mediterranean shell, I cannot speak 

 to that point. 



24. Rissoa (Otwba) brachia, 1 n. sp. (PI. XLV. fig. 8). 



Station 24. March 25, 1873. Lat. 18° 38' 30" N., long. 65° 5' 30" W. North of 

 Culebra Island, West Indies. 390 fathoms. Pteropod ooze. 



Shell. — Small, thin, ovate, conical, trauslucent, umbdicated, with a large rounded tip, 

 convex whorls, an impressed suture, a short round base, a strongly varixed lip, and a 

 round mouth. Sculpture : Longitudinals — there are only slight lines of growth. Spirals 

 — there are on the penultimate whorl five remote spiral threads, the three in the middle 

 are prominent and distinct, the one below the suture is feeble, and the lowest is hid in the 

 suture ; pn the base of the shell they are weak ; the parting furrows are twice as broad as 

 the threads ; both threads and furrows are very finely fretted with microscopic spiral lines 

 (as in Rissoa striata, Adams). Colour translucent white. Spire very short and stumpy. 

 Apex large, round, and glossy, but sparsely dotted with microscopic stipplings, which seem 

 to run in spirals. Whorls 4, rounded, of regular increase ; the last is tumid. Suture 

 scarcely oblique, impressed. Mouth round. Outer lip sharp, with a strong external varix, 



1 ft<«X"?, /%<*%"«, short. 



