Fig. 325.—Ancylostoma duodenale: showing ventral teeth, dorsal cleft, and behind it the dorsal ridge with duct of dorsal œsophageal gland. × c. 200. (After Looss.)
Œsophageal Glands (3).—The chitin of the triradiate œsophagus is continuous with that of the buccal capsule. In its muscular walls are three glands—one dorsal, two sub-ventral. The dorsal gland opens into the buccal cavity through the dorsal ridge; the two others into the lumen of the œsophagus at the nerve ring. They branch freely amidst the muscles. They are probably digestive in function.
Cephalic Glands (2).—Lie in the lateral lines or bands on either side. They begin about the middle line of the body, and their ducts open at the base of the outer ventral tooth on the surface of the skin on each side. Each is 0·15 mm. thick in the middle, and has a single nucleus about as big as an ancylostome egg (N, fig. 323). They probably function as poison glands.
Excretory System and Cervical Glands (2).—The excretory pore lies in the mid line ventrally behind the œsophageal nerve ring (figs. 324 and 326). It opens into the excretory vesicle, a cavity in a large cell with lateral appendages which fuse with the lateral lines, this cell thus forming the “bridge” of the excretory system. Adhering to this (bridge) cell are the spindle-shaped cervical glands (Glc, fig. 324), and branches from the excretory vesicle enter the glands, which are excretory in function; the vesicle also receives branches from the lateral excretory canals (fig. 326) running in the lateral lines or bands. The cervical glands are swollen anteriorly, forming the so-called ampullæ just in front of the bridge. They extend backwards a little beyond the anterior loop of the testis.
Fig. 326.—Ancylostoma duodenale: diagrammatic representation of excretory system. ex.p., excretory pore; e.c.g., excretory cervical gland; Ex. ves., excretory vesicle in B.c., bridge cell, which is connected with c.g., cervical gland, and l.l., lateral lines; ceph.g., cephalic gland; l.ex.c., lateral excretory canal passing into the bridge cell; l.l., lateral line containing excretory canal and cephalic gland; c.p., cervical papilla; n., nuclei of bridge cell. (After a drawing of Looss.)
Lateral Lines.—(1) Are broad elevations of the subcuticle, in which, here and there, a nucleus occurs. (2) Near the bursa in the male they increase in volume, and finally divide into branches which form the “pulp” of the different rays. (3) In addition to the lateral lines or bands, there is also a dorsal and ventral band. (4) The ventral band is well developed caudally, forming a large pad dorsal to the cloaca, “pulvillus post-analis.”