158 



J.D. TAYLOR, Y.I. KANTOR AND A.V. SYSOEV 



DIAGNOSES OF HIGHER TAXA 



Family Drilliidae Morrison, 1966 (ICZN pending) 



Shell of small to medium size (usually 15-25 mm, up to 50 

 mm), claviform (with a more or less high spire, and a 

 relatively short, truncated base). Anterior canal indistinct, 

 short or moderately elongate. Anal sinus on the shoulder, 

 rather deep, often sub-tubular when a parietal tubercle is 

 present. Sculpture usually well developed. Protoconch pauci- 

 or multispiral, smooth or, sometimes, carinate (from the 

 second whorl or, rarely, from the beginning). Operculum 

 with terminal nucleus. 



Radula. With strong radular membrane, five teeth in each 

 row, with in some species the complete loss of the central 

 tooth and reduction of the laterals. Rachidian tooth small, 

 with a prominent central cusp and, often, smaller lateral 

 denticles. Lateral teeth are typically broad and curved, 

 comb-like, with many small cusps the outermost being 

 smaller. Marginal teeth have a variable morphology from 

 simple and flat, sometimes with a weak accessory limb, to 

 enrolled. In at least one species (Imaclava unimaculata) , 

 marginal teeth are hollow and enrolled, whilst the radula as a 

 whole is similar to that of other drilliids. 



Foregut. Proboscis moderately long, with one or two distal 

 sphincters and sometimes a mid-buccal tube sphincter. Buccal 

 mass at base of proboscis, odontophore well-developed, 

 cartilages either separated or fused. Two acinous salivary 

 glands with two ducts. No accessory salivary glands. Venom 

 gland with uniform histology along its length. Retractor 

 muscle of the radular sac passes through the nerve ring and 

 joins the columellar muscle. 



Remarks. The anatomy and radula are known for only a 

 very few species of Drilliidae. This prevents us from introduc- 

 ing any subfamilial classification of this possibly complex 

 family. 



Family Terebridae Morch, 1852 



Elongate, multiwhorled shells, with small quadrate to trian- 

 gular apertures. Siphonal canal short. Anal sinus not visible. 

 Shell ornament of low axial ribs and grooves, spiral grooves, 

 a few species with tubercles, shells often smooth and pol- 

 ished. Protoconch of 1.5-5 whorls. Operculum rounded with 

 terminal nucleus. Radula with solid sickle-shaped teeth, 

 hollow harpon-like teeth or absent. Rhynchodeal introvert 

 present. Accessory proboscis structure and rhynchodeal sep- 

 tum present in some species. Proboscis present or absent. 

 Odontophore present in some species. Radular caecum 

 present in some. Acinous salivary glands present. Accessory 

 salivary glands present in some species. Venom gland present 

 or absent. 



Subfamily Pervicaciinae Rudman, 1969 



Shells medium to large, elongate, multiwhorled, anterior 

 canal short, ornament low axial ribs, spiral grooves, often 

 with a subsutural groove. Aperture quadrate. Operculum 

 rounded with terminal nucleus. 



Radula. With strong radula ribbon, two rows of sickle- 

 shaped solid marginal teeth. 



Foregut. Rhynchodeal introvert. Rhynchodeal septum and 

 accessory proboscis structure present in some species. Pro- 

 boscis absent. Extensible buccal lips present in some species. 

 Odontophore with two cartilages. Two acinous salivary 

 glands and ducts. Venom gland and accessory salivary glands 

 absent. 



Subfamily Terebrinae Morch, 1852 



Shells medium to large, elongate, multiwhorled. Small quad- 

 rate to triangular aperture. Short siphonal canal. Shells often 

 smooth and polished. Shell ornament of low axial and spiral 

 ribs and grooves. 



Radula. Where present, long, hollow marginal teeth with 

 narrow bases, barbed or unbarbed. Hastula bacillus has 

 semi-enrolled teeth with a distal solid blade. Many species 

 have no radula. 



Foregut. Rhynchodeal introvert present. Rhynchodeal sep- 

 tum and accessory proboscis structure present in some spe- 

 cies. Proboscis long, medium or absent. Odontophore with 

 cartilages present in some Hastula species. Radula caecum 

 present in many radulate species. Acinous salivary glands 

 with two ducts usually present. Accessory salivary glands 

 present in some species. Venom gland present or absent in 

 radula-less species. 



Family Pseudomelatomidae Morrison, 1966 



Shells of medium to large size (35-77 mm), fusiform. Ante- 

 rior canal moderately elongate. Anal sinus on the shoulder. 

 Protoconch smooth. Operculum with terminal or subcentral 

 nucleus. Egg capsules dome-shaped, with an operculum. 



Radula. With strong radular membrane; three teeth in each 

 radular row. Rachidian is large and rectangular with a large, 

 curved and pointed, central cusp and smaller lateral cusps. 

 Marginal teeth are solid, simple and curved. 



Foregut. Proboscis very long, no anterior buccal tube 

 sphincter; buccal mass basal or posterior of the proboscis 

 base. Oesophagus elongated between the buccal mass and 

 nerve ring in Pseudomelatoma . Odontophore very large with 

 fused cartilages. Acinous salivary glands, paired in 

 Pseudomelatoma, but unpaired with a single duct in Hormo- 

 spira. No accessory salivary glands. Venom gland with uni- 

 form histology. 



Family Strictispiridae McLean, 1971 



Shell of rather small size (usually 15-20 mm), claviform. 

 Anterior canal short or indistinct. Sculpture well developed. 

 Deep subtubular sinus is situated on the concave shoulder 

 and bordered with well developed parietal callus. Protoconch 

 smooth, multispiral. Operculum with terminal nucleus. 



Radula. with strong radular membrane; 2 teeth in each 

 row, central and lateral teeth absent (latter maybe diapha- 

 nously on optical preparations). Marginal teeth solid, awl- 

 shaped, with pointed tips, a broad base and a mid-tooth 

 flange . 



