SUBGENUS ANATONCHUS 



(S.s.475) 173 



innervated papillae of smaller size. The supplementary organs are plainly inner- 

 vated and the nerves can be traced through the cuticle and through the body mus- 

 culature, and seem to be connected with internal more or less ellipsoidal cells whose 

 nature remains unknown. The spinneret is very inconspicuous. The nature of the 

 caudal glands remains uncertain. 



Found in marshy ground, Arlington Farm, Virginia, U. S. A., about the roots of 

 fmpatiens, in black, clayey soil, with mud. Resembles M. dolichurus to a certain 

 extent. It is regrettable that only a few specimens have been available for exami- 

 nation, as it is a species well adapted to throw light on various features of mon- 

 onch anatomy. Fig. 56 (on the previous page). 



Examination of the pharyngeal muscles of this species leads to a partial under- 

 standing of the mechanics of the lips. The muscles which move the lips are long 

 and slender, and pass from the lips backward along the surface of the pharyngeal 

 capsule. They join the body wall some distance behind the pharynx. There are 2 

 separate groups of muscles, extensors and flexors. Of the 6 extensors 2 are shown 

 in the illustration ; these are furcated opposite the middle of the pharynx, one half 

 of each going to the lateral lip; the other half to a submedian lip. The joined 

 fulcra of the 6 lips form a framework encircling the head. The extensors pass 

 outside this framework. The flexor muscles are less clearly shown, but are mani- 

 festly better developed. A group of 3 is shown lying between the 2 extensors. 

 They appear as faint bands outside the pharynx passing forward, and beyond doubt 

 are attached to the lips inside the ring of fulcra. The musculature of the lips is 

 shown in the illustration and is further explained on page 140 in connection with 

 the general description of the head. 



45. M. dolichurus Ditlevsen. Neck tapering but little. Pharynx probably 

 prismatic, and in transverse section somewhat triangular. About 7 denticles about 

 the base, or near the base, of the pharynx. The arcuate tail tapers to the terminus, 

 which is about one-eighth as wide 

 as the base. The author mentions 



* ' ? . 2.5 1.8 



the presence of 3 or 4 inconspicu- 

 ously developed lobes at the base 

 of the oesophagus, and it would 

 appear from his figures that a spin- 

 neret and caudal glands are pres- 

 ent, the latter forming a tandem 

 series near the anus. Menzel finds 

 in the pharynx of Swiss specimens ^ 

 of this species 3 teeth of equal size ; 

 that is to say, the ventrally sub- 

 median teeth are equal in size to 

 the dorsal tooth. His specimens 

 are / 2 to 5}/2 mm. long, and this 

 probably represents the adult size, a 



Found in moist soil and meadow 

 land, Jutland; Switzerland. Fig. 

 57 (after Ditlevsen). Menzel shows 

 the papillae as much less conspicu- 

 ous, and without the spherical tips. 

 The original material consisted of 

 but a single immature female. 



