DEEP-SEA CONOIDEAN GASTROPODS 



23 



asymmetrical, with the apex situated just below the middle of the 

 subsutural slope. H = 30.2, Hb = 17.4, Ha = 13.9, D = 8.8 mm. 



The paratypes vary in details of spiral sculpture, especially on 

 the subsutural slope, where several rather strong and evenly 

 spaced riblets may be developed. In some paratypes the spiral 

 cords are more numerous, closely spaced on the canal and more 

 or less irregularly distributed over the body whorl surface. There 

 may be from 13 to 15 axial folds on the body whorl. The largest 

 paratype has H = 32.0 and D = 9. 1 mm. 



Operculum is small, oval, with terminal nucleus. Radular 

 teeth are long and narrow, more or less curved, without a solid 

 base, rather large (0.74 mm on the average at H = 27.8 mm). 



The new species resembles the type species of Typhlomangelia, 

 Pleurotoma nivale Loven, 1846, differing well in the elongate 

 shell with a high spire and prominent spiral ribs. 



Distribution. Maldive Islands, 797 m. 



Genus TYPHLOSYRINX Thiele, 1925 



Type species: Pleurotoma ( Leucosyrinx ) vepallida von Martens, 

 1902 (original designation) 



Typhlosyrinx praecipua (E.A.Smith, 1899) 



Fig. 101 



Pleurotoma (Surcula) praecipua E.A.Smith, 1899, p. 239; 



Annandale & Stewart, 1 9 1 0, pi. 2 1 , figs 4, 4a. 

 Typhlosyrinx praecipua (E.A.Smith) Powell, 1969, p. 360-361, 



pi. 272, figs 2, 3. 



Type locality. 'Investigator', stn 229, off Travancore coast 

 (India), 360 fms. 



Material, stn 184, 1 shell. 



The shell from stn 184 (H = 30.2 mm) corresponds quite well 

 with the description and illustration of the type specimen. Axial 

 folds (11 on the penultimate whorl) abruptly disappear on the 

 border between the penultimate and body whorls. The spiral 

 sculpture is developed only on the whorl periphery and the shell 

 base, and consists of low, broad, flattened, wavy riblets unequal 

 in width and separated by narrow grooves. 



Distribution. India and Gulf of Aden, 658-1 270 m. 



Genus GLYPHOSTOMA Gabb, 1872 



Type species: Glyphostoma dentiferum Gabb, 1 872 (monotypy) 



Glyphostoma maldivica Sysoev, new species 



Figs 1 02 & 103 



Material, stn 145, 1 shell (holotype No. 1993109). 



Description. The shell is rather small, thick, solid, 

 yellowish-white, and consists of the protoconch and 5 3/4 

 teleoconch whorls. The protoconch consists of 3 whorls; its 

 initial part is represented by 1.5 rapidly increasing 

 semi-transparent, smooth whorls followed by more solid angled 

 whorls sculptured below the periphery by a narrow keel. The 

 teleoconch whorls are concave below the suture and angled at 

 the periphery. The sutures are clear, shallow, and wavy. The shell 

 base is weakly convex and passes smoothly into the canal. The 



shell surface is distinctly and minutely granular, the granulation 

 is better seen in the interspaces between the axial folds. The 

 growth lines are mostly indistinct. The axial sculpture is 

 represented by rounded folds extending from the subsutural 

 slope to lower suture and, on the body whorl, to the canal. There 

 are 24 such folds on the body whorl and 1 9 on the penultimate. 

 On the subsutural slope, the axial sculpture consists of 

 numerous curved and rather weak folds with sharpened crests. 

 They generally represent the continuation of main axial, folds 

 but there may also be interstitial folds; as a result, the subsutural 

 slope of the body whorl is covered with 32 folds. The spiral 

 sculpture is represented by strong ribs almost equal in 

 prominence to the axial folds. At the intersection with axial 

 sculpture, the ribs form rounded tubercles. The interspaces 

 between spiral ribs are covered by closely set threads. The ribs on 

 the subsutural slope are much smaller corresponding to much 

 smaller axial folds. The aperture is elongate-oval. The inner lip 

 bears two rather prominent pointed tubercles in its middle part 

 and several smaller ones in the lower part. The outer lip is 

 sharpely and wavely edged and bordered by a heavy curved 

 varix. The inner surface of the aperture bears one strong 

 tubercle in the upper part and a group of 5 tubercles below. The 

 anal sinus is deep, U-shaped, bordered with callus and 

 constricted at its entrance by a heavy tuberculated callus pad. 

 The canal is straight along most its length and slightly curved 

 backwards near the end. H = 1 7.6, Hb = 1 1 .8, Ha = 9.8, D = 8.6 

 mm. 



In general outline the new species is most similar to 

 Clathurella perlissa E.A.Smith, 1904 from the Andaman Islands 

 but differs in the character of sculpture and apertural 

 armament. The species corresponds well to the genus 

 Glyphostoma in all important conchological characters such as 

 characteristic protoconch, granular surface, prominent 

 subsutural slope with different sculpture (in contrast to Etrema), 

 and strong intersecting spiral and axial ribs. 



Distribution. Maldive Islands, 494 m. 



Glyphostoma supraplicata Sysoev, new species 



Figs 104 & 105 



Material, stn 176, 6 shells (holotype No. 1993110 and 5 

 paratypes No. 1993111). 



Description of holotype. The shell is rather small, slender, 

 fusiform, relatively solid, white, consists of protoconch and 

 almost 7 teleoconch whorls. The protoconch consists of 3.5 

 whorls, the tip is small and papillate. Initial embryonal whorls 

 are smooth, the two last whorls angled, with a cord-like 

 peripheral keel, the second weaker keel encircles the lower 

 suture. The spire is tall, occupies about 0.4 of the shell height. 

 Definitive whorls are angled at the shoulder and in the lower 

 part, the subsutural slope is weakly concave or almost flat. The 

 sutures are clear, shallow, slightly wavy. The entire shell surface is 

 densely and minutely granulated, but the granulation more or 

 less disappears on prominent parts of the sculpture. Growth 

 lines are thin and irregularly elevated. Axial sculpture consists of 

 strong, oblique, rounded folds separated by interspaces 

 approximately equal in width to the folds. The folds reach the 

 canal, gradually weakening on the shell base. On the subsutural 

 slope, they are much weaker, narrower, almost obsolete near the 

 upper suture, and curved in correspondence to the anal sinus 

 scars. There are 15 folds on the body whorl and 13 on the 

 penultimate. Spiral sculpture is represented by broad cords 



