70 



Y.I. KANTOR, A. MEDINSKAYA AND J.D. TAYLOR 



ire bm 



Fig. 16 Nquma scalpta Kilburn, 1988. A, Semidiagrammatic longitudinal section of the foregut (salivary ducts not shown); B, longitudinal section of the 

 proboscis tip showing a gripped marginal tooth. 



posterior of the rear of the proboscis. It has relatively thin walls and 

 a narrow inner cavity which is uncurved. Extensible buccal lips are 

 absent. The oesophagus is elongated between the buccal mass and 

 nerve ring, forming a rather long loop. 



Glands 



The salivary glands are large, fused and acinous. The ducts are 

 paired, very long, coiled, thick and leave the gland at the same place. 

 The venom gland changes histology after its anterior passage through 

 the nerve ring. The duct of the gland is narrow, ciliated, long and 

 coiled, and opens into posterior part of the buccal cavity. The wall of 

 the muscular bulb is formed of three layers, the two outermost being 

 divided by a connective tissue layer, with a very thin innermost layer 

 of circular fibres. The two outer layers are formed from longitudinal 

 muscle fibres, the outer being twice as thick as the inner. 



Odontophore and radula 



The odontophore is small, with paired and unfused, odontophoral 

 cartilages. The buccal sac is short. The radula (Fig. 17a) consist of 

 marginal teeth, with each wishbone tooth formed of two elements. 

 The major element is robust and solid with a distal point. The 

 secondary element is smaller (0.6 of the major element), thinner and 

 terminates before the base of the tooth. The marginal tooth is 

 medium long, ca. 1 30pm ( 1 .3% of SL, 2.7% AL). 



Naudedrillia praetermissa (Smith, 1904) 



The foregut anatomy is similar in general pattern to that of Nquma 

 scalpta and differs in the position of the buccal mass, which lies 

 totally posterior to the proboscis, and the more developed but 

 nevertheless still short buccal lips. The striking difference is that in 

 N. praetermissa the salivary glands are tubular, large and highly 

 coiled, with a rather wide inner lumen. The ducts are very short, of 

 similar diameter to the glands, but ciliated. 



A radular tooth was seen in the sac-like enlargement of the buccal 

 tube, attached to the epithelial pad. The radula consists of marginal 

 teeth (Kilburn, 1988, fig. 52), with each tooth comprising two 

 components; a large major element which is an elongate, grooved 

 and twisted blade, with a distal point and a shorter minor element 

 which is attached about halfway along the major element. The 

 marginal tooth is long, ca. 160pm (1.3% of SL, 3.5% AL). 



Epidirona gabensis (Hedley, 1922) 

 (Fig. 18a) 



Rhynchodeum and proboscis 



The rhynchostomal sphincter is large and posteriorly located. The 

 rhynchocoel is very long and narrow. The epithelium of nearly the 

 whole rhynchodeal cavity is tall, glandular, folded and formed of 



