126 



H.W. PALM AND T. WALTER 



3c 



Fig. 3a-c Strobila of Nybelinia southwelli sp. nov. a. acraspedote arrangement of the proglottids with characteristic convex margins, b. mature proglottid 

 with the large cirrus sac and oviform testes, c. gravid proglottid. Scale bar b=100 urn and scale bar c=l 10 urn. 



more slender and slightly curved; L=7.5-10.0, B=8-9. The basal 

 armature is heteromorphous (Fig. 5b). The basal hooks are of the 

 same shape and size as those in the metabasal region of the tentacle. 

 External surface hooks, L=10.5-11.5, B=10.5— 1 1.8; internal hooks, 

 L=6.5-8, B=8-9. 



The morphology of the mature proglottid of N. perideraeus 

 (VNHM 2109) is given as Fig. 6. N. perideraeus has a long 

 acraspedote strobila of about 300 proglottids (strobila on 2 slides). 

 While the anterior proglottids are wider than long (520-560 x 266- 

 300), the final proglottids are longer than wide (559-741 x 520-530), 

 and continuously increasing in size. The genital atrium is 

 ventrosubmarginal in about the anterior third of the proglottids and 

 alternates irregularly. The cirrus sac is elongate (254 x 60), directed 

 anteromedially 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 ar- 

 ranged in double layer, number 86-97, ovoid, 33-49 in diameter, 

 encircle the female genital complex, and some testes are present 

 anterior to the cirrus sac. Other details of the female genital complex 

 not seen. 



Remarks. 



In the original description of Tetrarhynchus perideraeus, Shipley & 

 Hornell (1906) described long worms with a slender scolex bearing 

 long bulbs as well as slender tentacles. The tentacles as well as the 

 tentacular sheaths are short and the tentacular armature consists of 

 oblique rows of very minute hooks of uniform size. However, these 

 characters do not adequately define the species. Dollfus (1930) 

 remarked that without examination of the original material, N. 

 perideraeus is not distinguishable from N. lingualis. A description 

 of Stenobothrium perideraeum by Pintner (1930) did not consider 

 the form and arrangement of the tentacular armature, and thus, was 

 not helpful in solving this taxonomic problem. Southwell (1924, 

 1929a, 1930) described specimens which he named N. perideraeus. 

 However, Pintner (1930) noticed that the material observed by 

 Southwell (1929a, 1930) belonged to a different species. 



Dollfus (1942) gave a description of A 7 , perideraeus, summarising 

 the information given by Shipley & Hornell (1906) and Pintner 

 (1930), and illustrated the species on basis of material collected 

 from Carcharhinus melanopterus (Quoy & Gaimard, 1824) from 

 the Gulf of Suez, Egypt. While remarking that the descriptions of the 





