Parasitic worms, with a note on a free-living nematode / by R.T. Leiper and E.L. Atkinson.

  • Leiper, Robert Thomas, 1881-1969.
Date:
1915
Catalogue details

Licence: In copyright

Credit: Parasitic worms, with a note on a free-living nematode / by R.T. Leiper and E.L. Atkinson. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    practical acquaintance with these methods before starting on the Expedition, and for the facilities afforded in the Helminthologica] Department for working out the material upon his return. The elucidation of the anatomical structure of the various forms and the descriptive account of the Cestodes are largely the work of Surgeon Atkinson. NEMATODA. FKEE - 1,1 VINO NEMATODES. Tj'ptoMomatum, Bastian, L 865. L. Leptosomatum setomm, v. Linstow, L896. (Plate I, figs. 3, C>, 9.) A tube containing a large number of this species occurred in the collection made by Mr. Lillie from a depth of 250 fathoms in McMurdo Sound. Specimens were also collected from a depth of 150 fathoms off Inaccessible Island, Lat. 77 38' S. (Stat. 320). The vitreous appearance of the cuticle distinguishes this species from parasitic forms. The cuticle is not striated, but carries fine acicular spines in longitudinal rows mi the anterior part of the body, and, in the male, on the ventral aspect in the region of the genital papillae and the anogenital opening. Both extremities of the worms are bluntly rounded. The head-end is somewhat the more abruptly truncated. The head has a subcuticular shield of chitinous substance which gives these forms an exceedingly characteristic appearance (PI. I, fig. 3, it). This is shown in optica] section in PI. I, fig. !). a. The arrangement of the spines on the head has not been fully elucidated. They extend in linear series from the tip of the head backwards for a distance of about (')• I 2 mm. (Fig. 9, b). In a male, 15 mm. long, the nerve-ring (PI. I, fig. 3, </) crosses the oesophagus at O'tio mm. behind the head. The oesophagus measures 2-3 mm. (Fig. 3, b). The testicular lube is a thick solid tube ending anteriorly at 46 mm. from the head in a blunt digitate process. It passes directly backwards without coiling to the anogenital aperture, which lies 0-5 mm. in front of the blunt and rounded tail. The spicule is a bent, short chitinous structure not unlike a boot-last in outline (PI. 1, fig. 6, sp). There is a well-developed shoe-shaped accessory piece (up). The genital papillae are sessile and are all preanal. There are four on one side and. usually, five on the other (PI. I, tig. (!, />). On either side of the middle line is a row of acicular spines. In the male there is also a series of diagona] muscular bands which bring about the ventral coiling of the posterior end of the body, extending forward for I nun. from the anogenital aperture. In the midventral line there is a, curious little chitinous ring surrounding a. sunken disc (Fig. 6, *), recalling the relatively large sucker seen in TIeterakis.