14 



A.V. SYSOEV 



and are most prominent in the whorl periphery. Spiral ribs are 

 strong, cord-like, narrow, widely spaced (but become 

 progressively closer to each other and lower on the shell base and 

 canal); they override the axial folds and form nodules at 

 intersections. Interspaces between ribs are very finely spirally 

 striate and sometimes bear a thin thread. The number of ribs 

 increases from 3 to 5 in successive spire whorls. The subsutural 

 fold is sculptured by two thin spiral riblets. Subsutural slope is 

 smooth except for very fine spiral striations and 3-4 thin threads 

 in the lower half. Growth lines are numerous, thin, and clear, on 

 the body whorl some of them are rough and raised. The shell 

 base is almost flat and not differentiated from the canal. The 

 aperture seems to be rather wide (the outer lip is broken). The 

 inner lip is weakly and evenly curved, and covered by thick 

 callus. The parietal callus pad is very weak. The anal sinus 

 (judging from its scars) is moderately deep, openly U-shaped 

 (type (c) of Kilburn, 1988). The canal is broad and widely open. 

 H = 39.5, Hb = 21 .4, Ha = 16.5, D = 10.8 mm. 



The new species resembles /. coxi (Angas, 1867) from 

 south-eastern Australia in whorl outline and the character of 

 sculpture but clearly differs in the shell proportions. It also looks 

 somewhat like an extremely stretched out specimen of /. crassa 

 (E.A.Smith, U 



Distribution. Gulf of Aden, 528 m. 



Genus PARADRILLIA Makiyama, 1940 



Type species: Drillia dainichiensis Yokoyama, 1923 (original 

 designation) 



Paradrillia agalma (E.A.Smith, 1906) 



Figs 59-61 



Pleurotoma (Surcula) agalma E.A.Smith, 1906, p. 162-163; 



Annandale & Stewart, 1909, pi. 21, figs 4, 4a. 

 Paradrillia agalma (E.A.Smith) - Powell, 1969, p. 317, pi. 246, 



figs 1,2. 



TYPE LOCALITY. 'Investigator', stn 269, West of Cape Comorin 

 (SE India), 464 fms. 



Material, stn 176, 1 shell; stn 180, 2 shells. 



The shell from stn 176 is quite typical. It consists of protoconch 

 and 7 teleoconch whorls. The previously undescribed 

 protoconch is basically similar to that of P. melvilli figured by 

 Powell (1969, pi. 242, fig. 2). It consists of 2.5 whorls with 

 smooth glossy surface, the tip is small and papillate, and a thin 

 low-set keel is developed on the last whorl. There are 1 7 axial ribs 

 on the body whorl and 1 5 on the penultimate one. 



The shells from stn 180 (Fig. 61) were referred to P. agalma 

 with some doubts. They differ in more numerous peripheral 

 tubercles, weaker axial and spiral sculpture, and in the presence 

 of two spiral threads on the subsutural fold and two riblets 

 below the periphery on the spire whorls. They seem to be a 

 transition to P. melvilli Powell, 1969 in sculpture, but that species 

 is almost half the size, with a proportionally higher spire and 

 truncated anterior end. However, the general pattern of 

 sculpture, shell outline and the character of protoconch are 

 similar in all JME shells and those from stn 1 80 are provisionally 

 assigned to P. agalma pending examination of additional 

 material. 



Distribution. Ceylon and Gulf of Aden, 655-848 m. 



Genus CERITOTURRIS Da\l, 1924 



Type species: Ceritoturris bittium Dall, 1924 (original 

 designation) 



?Ceritoturris sp. 



Fig. 62 



Material, stn 42, 1 shell. 



A single heavily damaged shell (H = 1 1.8 mm) from stn 42 can 

 possibly be referred to Ceritoturris on the basis of its 

 resemblance to both type species and C. nataliae Kilburn, 1988. 

 The very bad condition of the shell renders more precise 

 identification impossible. 



Distribution. West Arabian Sea, 1415 m. 



Genus PTYCHOBELA Thiele, 1925 



Type species: Clavatula crenularis Lamarck, 1816 (= Murex 

 nodulosus Gmelin, 1791) (original designation) 



Ptychobela cf. suturalis (Gray, 1838) 



Figs 79 & 80 



Drillia suturalis Gray, 1838, p. 29. 



Ptychobela suturalis (Gray) - Kilburn, 1989, p. 190, figs 5-6 

 (holotype)&7-8. 



Type locality, unknown. 



Material, stn 35, 1 shell; stn 188, 2 shells. 



These shells are difficult to determine primarily due to the 

 existence of numerous species of uncertain status which have 

 been described within the genus Drillia and, as far as it can be 

 judged from drawings (when present) and rather brief 

 descriptions, are similar to the JME material (e.g. Drillia incerta 

 E.A.Smith, 1877, D. atkinsoni E.A.Smith, 1877, D. variabilis 

 E.A.Smith, 1877, etc.). The question cannot be resolved without 

 comparative examination of type material. Nevertheless, these 

 shells are quite comparable with the holotype of P. suturalis 

 illustrated by Kilburn (1989). The latter species is however 

 characterized by usually very short axial folds with strong 

 peripheral nodules (but the folds in the holotype are rather long 

 - see Kilburn, 1989, fig. 6). The smaller of the JME shells (stn 

 188, H = 22.7, D = 7.6 mm, Fig. 80) differs also in complete 

 absence of additional spiral threads in the interspaces between 

 main cords. The other shell (stn 188, H = 22.9, Hb = 15.6 mm, 

 upper spire whorls are broken off and only 3.5 last whorls are 

 intact) also lacks additional threads on upper spire whorls, but 

 they appear on penultimate whorl and become rather strong on 

 the body whorl. The anal sinus is similar in shape to that of P. 

 suturalis, but some of the sinus scars indicate that during the 

 shell growth the sinus may be quite different: very deep and 

 narrow, asymmetrical, with the upper edge of the slit almost 

 parallel to the suture. The rather large shell from stn 35 (H = 

 3 1 . 1 , D = 1 1 .0 mm, Fig. 79) is characterized by fairly long axials 

 reaching the lower suture and a peculiar spiral sculpture of ribs 

 with the upper (directed adapically) slope being much steeper 

 than the lower. This produces a somewhat tiled pattern and, 

 when illuminated from the shell apex, the sculpture seems to 

 consist of very wide flattened ribs. 



