106 THE VOYAGE OF H.M.S. CHALLENGEE. 



Segnenzia formosa, Watson, Prelim. Keport, pt. 3, Journ. Linn. Soc. Lond., 1878, vol. xiv. p. 587. 

 „ monocingulata, Seguenza, Form. terz. Eeggio Calabria, pp. Ill and 272. 



formosa, Dall, "Blake" Moll., Bull. Mus. Comp. ZooL Camb., U.S.A., 1880, vol. ix. p. 47. 

 „ „ Verrill, Moll. N. Eng. Coast ; Trans. Conn. Acad., vol. vi. (in en: vii.) 1884, p. 186, 



pi. xxxi. fig. 14 (shell), 14a (operculum), 14b (teeth). 



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

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



Station 56. May 29, 1873. Lat. 32° 8' 45" N., long. 64° 59' 35" W. Off Bermuda. 

 1075 fathoms. Coral mud. 



Var. lineata, Watson (PI. VII. fig. 1). 



Var. lineata, Watson, Prelim. Report, pt. 3, Journ. Linn. Soc. Lond., vol. xiv. p. 587. 



? Station 120. September 9, 1873. Lat. 8° 37' S., long. 34° 28' W. Pernambuco. 

 675 fathoms. Red mud. 



? Station 122. September 10, 1873. Lat. 9° 5' S., long. 34° 50' W. Pernambuco. 

 350 fathoms. Red mud. 



Habitat. — From N. Atlantic, 1450 fathoms. Bay of Biscay, Spain, and Portugal, 

 718-795 fathoms. Gulf of Mexico, 325 fathoms. 



Fossil. — In the Upper Miocene of Calabria, and in -the middle Pliocene at Trapani, 

 Sicily (Seguenza). 



Shell. — Small, conoidal ; spire high; base inflated, white, glossy, with high spiral 

 threads. Sculpture : Of spiral threads there are ten on the last whorl — one small, sharp, 

 just at the suture ; two, strong and sharp, of which the lower forms the basal carina ; the 

 upper, which is sometimes even the more prominent, lies a little higher than half-way 

 between the basal and the sutural spiral : on the base there are seven, very equal in strength 

 and in distribution — the first lies somewhat remote from the basal carina, and is separated 

 from it by a broad shallow furrow ; the last lies pretty close to the pillar and twines round 

 it. On the upper whorls only the sutural and supra-carinal spirals are seen. There are 

 microscopic spirals on all the surface. Longitudinals — there are many hair-like, sharply 

 projecting, flexuous striae, defining the lines of growth on the upper whorls, but these 

 become very faint on the later whorls. Colour pure white with pearly translucency when 

 fresh, but weathering opaque with a pearly gleam through the calcareous surface-layer. 

 Spire high and conical, in some specimens a little depressed. Apex small, rounded, slightly 

 tabulated, with the l£ embryonic whorl projecting, round and glossy but slightly roughened. 

 Wliorls 8, of slow and regular increase, angulated above, sharply carinated, inflated on the 

 base, which is also slightly angulated by the third infra-carinal spiral. Suture only doubt- 

 fully traceable (under the microscope) in the middle of the sutural spiral. Mouth per- 



