128 



H.W. PALM AND T. WALTER 



Fig. 6 Mature proglottid of Nybelinia perideraeus. Scale bar=100 um. 



Fig. 7 Scolex of Kotorella pronosoma (Nybelinia herdmani) from 

 Himantura imbricata. Scale bar=150 um. 



N. herdmani are summarised in Table 1 . In addition to these data, the 

 following characters were observed: The 4 bothridia of TV. herdmani 

 (Shipley & Hornell, 1906) have free lateral and posterior margins 

 with a distinct space between the bothridia (Fig. 7). The bothridial 

 margins seem not to be fused with the scolex even apically. 

 Prebulbular organs around the tentacle sheaths are absent and 

 muscular rings are not visible. 



The armature of Kotorella pronosoma was described by Euzet & 

 Radujkovic (1989) and Campbell & Beveridge (1994). The arma- 

 ture of the type material of N. herdmani is homeoacanthous, 

 heteromorphous (Figs 8a-b). The tentacular hooks on the 

 antibothridial tentacle surface increase in size towards the distal part 

 of the tentacle, the hooks on the bothridial tentacular surface are of 

 similar size along the tentacle. The metabasal hooks on the bothridial 

 surface are tightly packed and have a broad, diamond- shaped basal 

 plate (L=l 3.5-14.5, B=8). The distance between these hooks ap- 

 pears to be slightly wider towards the apical part of the tentacle. On 

 the antibothridial surface, slender and spiniform hooks without 

 enlarged basal plates increase in size towards the end of the tentacle. 

 The hooks are more widely spaced than on the bothridial surface. 

 Basal hooks: L=6-8, B=2-3; metabasal hooks: L=13-14, B=3^4. A 

 basal tentacular swelling is absent, hsr (basal)=8, hsr (metabasal)=6- 

 7. 



The morphology of the mature proglottid of N. herdmani is given 

 in Fig. 9. N. herdmani has a short acraspedote strobila of about 76 

 proglottids behind the velum. While the anterior proglottids behind 

 the velum are wider than long (345-360 x 20-40), their length 

 increases in size towards a rectangular shape (276-310 x 175-215). 

 The final proglottids are longer than wide (715-755 x 560-610). 

 The genital atrium is ventrosubmarginal, pre-equatorial and alter- 

 nates irregularly. The cirrus sac is elongate (242 x 70), directed 

 medially from the genital atrium and the sac is thin-walled. The 

 cirrus is unarmed, coiled within the sac and an internal seminal 

 vesicle was not seen; external seminal vesicle absent. Testes over- 

 lapping but arranged in single layer, number between 35^18. The 

 size of ovoid testes varies depending on number of proglottid 

 (anterior proglottids: 37^-7; median proglottids: 53-64; posterior 





