December 2007 - The Indian Society for Parasitology

104A.P. Nandiin the same buffer. The materials were then dehydrated its anterior extremity and a pair of large oval doublein ascending series of ethanol, transferred to 100% cephalic papillae at its base. Each double papilla isisoamyl acetate through the mixtures of ethanol and circumscribed by a groove on the cuticle and bears twoisoamyl acetate (3:1, 1:1 and 1:3). The specimens were openings of the canals of papillary nerve endings. Eachthen dried in a Hitachi HPC-2 (Japan) critical point ventrolateral lip (Fig. 3) bears a single lobular structuredrying apparatus, mounted on aluminum stubs and at its anterior extremity and a large oval double cephaliccoated with gold by an IB2 ion coater. Observation was papilla at its base towards the ventral surface. Inmade out with a Hitachi S-530 (Japan) SEM at a addition, there is a small, round external labial papilla,resolution of 50 ? and operating at an accelerating also surrounded by a groove, at its lateral surface (Fig.voltage of 15 kV.3, 4). The opening of amphid, surrounded by a circularRESULTS AND DISCUSSIONcuticular rim, is situated laterally anterior to theexternal labial papilla on each of the ventrolateral lips1. A. trilabium (Linstow, 1904) (Nematoda: (Fig. 3, 4). Immediately posterior to the lips there is aAscarididae)pair of cervical papillae on each lateral surface justanterior to the beginning of the cervical ala (Fig. 1, 3).Host: C. sinensisScanning electron micrographs of the tail of males (Fig.Location: Intestine5, 6) reveal that the conically pointed tail bears a pair ofnarrow caudal alae. Precloacal sucker bears a circularLocality: Burdwan, West Bengal, Indiacuticular rim with a small medial elevation at itsposterior margin. Anal opening is a transverse slitLinstow (1904) described A. trilabium from C. sinensis bordered by cuticular margin. Caudal papillae are 10from the nematodes in the collection of the Colombo pairs in number: 3 pairs pre-anal, 1 pair adanal and 6museum. Baylis (1936) redescribed the species based pairs postanal in position. Of the 6 pairs of post-analon the type specimens. Nandi et al. (1989) reported this papillae, one pair lies immediately behind the analspecies from India from the type host. The nematodes opening. Phasmids open laterally anterior to the lastobtained for this study are from the same host and the pair of post-anal papillae.same zoogeographical region as that reported by Nandiet al.SEM observation of the cephalic region of the presentmaterial reveals that the paired cephalic papillae on theMorphologically the worms in this study agree fairly dorsal lip and the single cephalic papilla on each of thewell with the description of A. trilabium given by Baylis ventrolateral lips are double papillae. External labial(1936) and Nandi et al. (1989). SEM study of the papillae and the opening of amphids were erroneouslycephalic region of the present material reveals that three described as cephalic papillae by earlier workers.well-developed lips bordered by cuticular ridge Present study clearly reveals the structural details of thesurround the mouth (Fig. 1). The dorsal lip (Fig. 1, 2) is cephalic papillae, external labial papillae and amphids.bluntly conical and bears a pair of lobular structures at Baylis (1936) reported 8 pairs of post-anal papillae in A.Fig.1. Anterior end of male, dorsal view.Fig. 2. Dorsal lip of male.