148 



D.J. GOWER AND M. WILKINSON 



Fig. 5 Uraeotyphlus cf. narayani (field tag MW 207). Views of (a) dorsal, and (b) distal and slightly ventral surfaces of phallus (everted cloaca). For 

 scale see Fig. 4. 



rm 



a.rvl 



Fig. 6 Uraeotyphlus cf. narayani (field tag MW 254). Dissected cloaca 

 of mature male. The cloaca has been opened mid-ventrally and pinned 

 to reveal the lumenal surface of the phallodeum and posterior part of the 

 urodeum. The incision has longitudinally bisected the right ventrolateral 

 longitudinal ridge so that parts of it lie on each side of the open cloaca. 

 Scale = 3 mm. 



longitudinal grooves at the anterior end of the phallodeum, at least 

 some of which may enter the blind sacs, where present (e.g. 

 Geotrypeles Peters, 1879, pers. obs.). 



POSTERIOR PHALLODEUM. The distinction between the anterior 

 and posterior phallodeum is sometimes less clear cut than that 

 between the phallodeum and urodeum. Wake (1972) reported that 

 the longitudinal ridges of the anterior phallodeum continue 

 posteriorly to the vent. We find that the major longitudinal ridges 

 reduce greatly posteriorly, either abruptly or gradually, that they 

 may or may not extend as far as the vent, and that the pattern of 

 ridges within the posterior phallodeum is irregular or less obviously 

 regular than those of the anterior phallodeum. The phallodeum 

 narrows dramatically posteriorly, shows considerable variation in 

 length, and has its terminal portion surrounded by a sphincter of 

 variable size. 



PHALLODEAL ORNAMENTATION. The major longitudinal ridges 

 of the anterior phallodeum may be more or less invested with, or 

 elaborated into, tuberosities, transverse ridges and grooves, longi- 

 tudinal crests, or spines that are often in distinctive patterns (e.g. 

 Figs. 6, 9). Isolated thickenings or other ornaments may also 

 occur in the spaces between the major longitudinal ridges. The 

 ridges associated with the dorsolateral sulci bear such features 

 only posterior to the sulci (e.g. Figs. 4, 7, 9). Both the shape and 

 arrangement of this ornamentation may be expected to provide 

 systematic characters, although there is also evidence of 

 intraspecific variation (e.g. Scolecomorphus, Wake, 1998). Species 

 appear to differ in whether the ridges within the posterior 

 phallodeum bear any ornamentation or not. Where present, as in 

 Typhlonectes compressicauda (Exbrayat 1996), they are not as 

 pronounced or distinctive as the structures of the anterior 

 phallodeum (distal phallus). 



Composition of phallodeal structures. The composition of 

 the main longitudinal ridges and their ornamentation is unclear from 



