Fig. 323.—Ancylostoma duodenale, male. B, bursa; Bm, bursal muscles; Cdr, cement gland surrounding the ejaculatory duct; Glc, cervical glands; N, nucleus of cephalic gland; Nr, nerve ring; T, testes; Sp, spicule; Vs, vesicula seminalis. × 15. (After Looss.)
Buccal Capsule.—The buccal capsule is bent dorsally, 0·21 mm. long, 0·19 mm. broad. If a worm is rolled under the cover-glass so that the dorsal side is upwards, we observe the following features (fig. 325): In the dorsal edge of the chitinous capsule there is a gap as if a U-piece had been punched out. This is the “dorsal gap or incision.” The so-called “dorsal teeth” are simply the rounded edges of the tips of this gap. They project beyond the skin which covers the capsule externally. Below this gap is seen a curved line which, if followed along the sides of the capsule on each side, merges into the base of the most posterior ventral tooth. This line is the optical expression of a very shallow groove on the inside of the capsule. The skin on the outside of the capsule, which is reflected over the edge of and into the capsule, dips into this groove, which gives it a firm attachment. Below the middle (dorsally) of this curved line there is a thickening in the capsule wall, which is perforated by the opening of the dorsal œsophageal gland. This is the “dorsal ridge”; in optical section it has a conical appearance with a lumen (of the duct).
Fig. 324.—Ancylostoma duodenale, female. A, anus; Gcph, cephalic gland; N, nucleus of cephalic gland; Glc, cervical gland; Ov, ovary; Pex, excretory pore; Rs, receptaculum seminis; Ut, uterus; V, vagina. × 15. (After Looss.)
Male 9 mm. long by 0·45 mm. thick, female 12 mm. long by 0·6 mm. thick. Pale flesh colour, or an intense red in posterior third. Anteriorly may be more or less black due to (blood) pigment in the cells of the chyle intestine (= stomach + small intestine). The worm is about the same thickness all through and is plump and rigid. Cuticle striated. The body has a marked torsion, so that if the ventral side of the head is upwards the anus appears to open laterally and vice versâ. The dorsal curve of the head end is only slight and the œsophagus is roughly cylindrical.
On the ventral wall one sees the two pairs of strong teeth, their points being directed somewhat backwards. They are covered by cuticle above and below, but their points are free, piercing the cuticle. The “roots” of these teeth followed backwards appear as two thickenings or ribs on the outside of the capsule wall, so that the outside wall is not smooth—a characteristic of the genus Ancylostoma. In the space between these ribs lies the ventral nerve papilla, and lying against the outside of the outer root the lateral nerve papilla. The nerve papillæ are thus, as it were, concealed by these roots, and not conspicuous as they are in Necator. Following the ventral curve of the capsule on the inside, posteriorly we next find two triangular ventral lancets.[316] These stand straight up into the capsule on either side of the longitudinal axis, converging at their summits. So that to sum up, the cutting apparatus is entirely ventral, consisting of two pairs of cutting teeth and a pair of lancets.
Cervical Papillæ.—Two, one on each side behind the head at the level of the excretory pore. They consist of “pulp,” i.e., extensions of the substance of the lateral bands covered by cuticle and supplied with a nerve (fig. 326).