224 



THE INVERTEBRATA 



Fig. 170, Nematodes parasitic in man. A, B and C, Ankylostoma. After Looss. 

 A, Adult worm attached to epithelium of small intestine of the host, with some 

 of the tissue of the latter sucked into the buccal cavity of the worm. d.g. dorsal 

 gland; la. lancet; oe. oesophagus; v.t. ventral tooth; tis. host tissue, lacerated 

 by the lancets and partly digested ; vil. villi of small intestine. B, Larvae pene- 

 trating the skin of mammal, x. through the horizontal fissures of the epi- 

 dermis; y. along the hair follicles; z. larvae which have arrived in the lymph 

 vessels of the subdermis ; ep. epidermis. C, Copulatory bursa of adult male, 

 spread out to show the arrangement of the rays. D. Dorsal; V. ventral; 

 sp. copulatory spicule. D, Filaria hancrofti, longitudinal vertical section 

 through a mosquito (Stegomyia) to show wandering of the larvae. After Bahr. 

 a, larvae just swallowed and now in the mid gut (mg.) ; some migrating through 

 the gut wall; b, larvae developing in the thoracic muscles (th.m.); c, larvae 

 which have finished development (8-15 days) migrating in the haemocoele 

 of the head ; d, larvae in the blood space of the labium, which they leave by 

 rupturing the body wall when the mosquito bites; cr. crop; ph. pharynx; 

 pr. proboscis ; sg. salivary glands. 



