EEPORT ON THE GASTEROPODA. 109 



Station 78. July 10, 1873. Lat. 37° 26' N., long. 25° 13' W. San Miguel, Azores. 

 1000 fathoms. Volcanic mud. 



Station 85. July 19, 1873. Lat. 28° 42' N., long. 18° 6' W. Palma, Canaries. 

 1125 fathoms. Volcanic mud. 



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

 675 fathoms. Ked mud. 



Habitat. — North Atlantic, 690 fathoms. "Porcupine" Expedition, 1870, Bay of 

 Biscay, off Spaiu and Portugal, 718-1095 fathoms. 



Shell. — Small, broadly conical, rounded on the base, sharply aagulated, umbilicate, 

 thin, polished, vitreous. Sculpture: There is a sharp circumbasal carina, which on the 

 spire sometimes projects a little above the suture, but is generally concealed by the 

 succeeding whorl. In the middle of the whorls is a slight spiral thread, which on the 

 earlier whorls is much stronger and somewhat lower in position than on the last ; it 

 defines the inferior edge of the generic sinus. The base is margined by a broad flat 

 flange, and the edge of the umbilicus is defined by a fine sharp thread. Besides these 

 there are some faint traces of microscopic spirals on the whole surface, especially on the 

 base ; and the basal sinus has on its outer edge more or less traces of a fine spiral thread. 

 Longitudinals — there are many hair-like flexuous lines of growth. Colour glassy when fresh 

 and young, in older shells opaque white, but even then showing only the faintest trace 

 of pearly nacre. Spire conical, rather depressed, and with a slight convexity of its con- 

 tour-lines. Apex very small and sharp, flattened on the one side, and with the minute 

 embryonic 1^ whorl projecting roundly on the other. Whorls 7, of gradual increase, 

 slightly convex above, flatter below, and a very little constricted above the sutural flange, 

 whose edge is sharp below and rounded above. The base projects rather sharply from 

 the inner side of the carinal flange, and then passes rather flatly across to the edge of the 

 umbilicus, into which it slopes steeply. Suture linear and a very little impressed. Month 

 perpendicular, almost square, but a little rounded both on the sides and at the angles. 

 Outer lip sharp and thin, not patulous, not descending ; the curves of its edges are similar 

 to those described in Seguenzia monocingulata, Seg., there being three sinuses, one near 

 the suture, a second at the carina, and a third toward the exterior of the base. Pillar-lip 

 is patulous and a little reverted, scarcely twisted, with a broad deep sinus above, a strong 

 twisted projecting tooth at about three-fourths of its length, below which is a smaller 

 sinus running out into a point at the extreme end of the pillar. Umbilicus large, funnel- 

 shaped, deep, defined by a fine spiral thread, which runs out to the point of the pillar-lip ; 

 within the umbilicus is a shallow furrow answering to the pillar-tooth, and above is 

 another spiral thread, stronger, but less sharp than that on the edge ; the curved lines 

 of growth are strongly defined in the umbilicus. H. 0"15 in. B. 0'17, least 0-15. Last 

 whorl 0-037. Mouth, height 0'049, breadth 0"5. 



