Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . pening intoventral vessel. As in other species, dorsal vessel passes anteriorly and entersproboscis. Remarks Important features of the present specimen include: the presence of anunusually large number of mesenteric strands attaching the gut to the body wall,the structure of the gonostomes, and the 1 : 4 ratio of the proboscis to the trunklength. Another distinguishing feature seems to be the small size of the sexuallymature specimen. Ochetostoma erythrogrammon, O. caudex, O. palense, O. australiense andO. indosinense
Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . pening intoventral vessel. As in other species, dorsal vessel passes anteriorly and entersproboscis. Remarks Important features of the present specimen include: the presence of anunusually large number of mesenteric strands attaching the gut to the body wall,the structure of the gonostomes, and the 1 : 4 ratio of the proboscis to the trunklength. Another distinguishing feature seems to be the small size of the sexuallymature specimen. Ochetostoma erythrogrammon, O. caudex, O. palense, O. australiense andO. indosinense possess three pairs of gonoducts and 12-22 longitudinal musclebands and hence appear to be related to this specimen from Park Rynie. The trunk length of sexually mature specimens of O. caudex ranges from72 mm to 105 mm (Biseswar 1983), and in O. erythrogrammon from 80 mm to160 mm (Stephen & Edmonds 1972). In both these species, the proboscis is one-third to three-quarters as long as the trunk. This sexually mature specimen of 70 ANNALS OF THE SOUTH AFRICAN MUSEUM m s. s r int r a v Fig. 21. Ochetostoma sp. Dorsal dissection of the trunk, showing thealimentary system and anal vesicles. Ochetostoma sp., however, is small, with a trunk length of only 40 mm and theproboscis is about one-quarter as long. In addition, this specimen has a proboscis in which the lateral margins uniteposteriorly to form a narrow lower lip. Another distinguishing feature of the present specimen lies in the structure ofthe gonostomes. The gonostomal lips, unlike those of O. caudex and O. erythro-grammon, are comparatively small and are not spirally coiled. Furthermore, in ECHIURA FROM SOUTHERN AFRICA 71
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
