404 EEV. E. BOOG WATSON ON THE 



slightly immersed. Whorls 7 in all, feebly keeled with a just 

 perceptibly concave line from the suture to the keel, and from 

 the keel to the suture below. Just above the suture there is a 

 slight contraction, which forms a faint superior margination. 

 The last whorl is very slightly swoln ; the base is rather rapidly 

 contracted, and is drawn out into a rather long, straight, but 

 not narrow snout. Suture distinct, impressed. Mouth almost 

 club-shaped, being pointedly oval above, with a longish rather 

 sinuous canal below. Outer Up forms a regular curve, till at the 

 canal it becomes flattened and oblique ; from the body it retreats 

 at once to form the rather deep, rounded, open-mouthed sinus, 

 from which it advances on a -very straight line to the edge of the 

 canal in front, where it bends slowly and slightly backwards ; it 

 is throughout open, but not patulous except at the point of the 

 canal. Inner lip spreads as a narrow porcellanous glaze on the 

 body and pillar; it is slightly hollowed out on the body, is straight 

 on the pillar, toward the front of which it is cut off with a narrow, 

 rounded, and very slightly oblique edge. H. 0'34. P>. 0"09. 

 Penultimate whorl, ' height 0'05. Mouth, height 0'14, breadth 

 0-05. \' ; ' ' V 



This species is very like P. emendat'aj~M.ontBvo%a.to (=P.Renieri, 

 Phil., but not really that of Scacchi) ; but is much narrower, has 

 much finer and differently arranged spirals, which are minutely 

 tubercled, the curved cusps of the old sinuses are much feebler, 

 and the longitudinals between the threads are far less distinct. 

 The apical whorls are much less depressed. 



13. Pleurotoma (G-enota) didyma, n. sp. (cUhv/j.os, doubtful.) 

 St. 23. March 15, 1873. Lat. 18° 24' N., long. 63° 28' W. 

 Sombrero Island, St. Thomas, Danish W. Indies. 450 fms. 

 Globigerina-oozQ. 



Shell. — High, mitriform, biconical, ribbed, and with spiral 

 threads ; the spire subscalar ; the mouth narrow ; the sinus 

 very slight. Sculpture. Longitudinals — the whorls are crossed 

 by eleven oblique, rather strong, but narrow hunchy ribs, with 

 broad open furrows between *; there are also very fine, close, hair- 

 like lines of growth. Spirals— the suture is not quite closely 

 marginated below by a rather slight thread; the sinus-area below 

 this is formed by a little open concave furrow ; below this is a 



* These ribs and furrows tend to disappear on the last whorl and they die 

 out on the base. 



