ART. 21 A NEW AMIDOSTOMINE WORM WETZEL 5 



The head is 33ju, to 36/x wide, being slightly wider dorsally and 

 ventrally than it is laterally. It is provided with a special cuticular 

 expansion forming four well developed head plates. The two lateral 

 plates occupying all the lateral portions and extending somewhat to 

 the dorsal and ventral side of the head have a slightly waved pos- 

 terior margin. The dorsal and the ventral plates showing the shape 

 of a spheric triangle are smaller, but well marked. The front sur- 

 face of the head is ornamented dorsally as well as ventrally with a 

 pair of conelike formations. They are arranged in a symmetrical 

 manner and have a length of about 8ju, to IO/a. Their pointed free 

 extremities are directed subdorsally and subventrally respectively. 

 These conelike ornaments correspond in every respect to the flaplike 

 formations of E. uncinatwin described above. The lateral papillae 

 or amphids are exceedingly well developed and prominent, occupying 

 almost the entire lateral portions of the head front. Each lateral 

 amphid is supported by a pair of glistening spinelike formations, 

 which are somewhat more developed than in E. unehiatum. The 

 four submedian papillae, each terminating in two points, are not so 

 prominent as the lateral amphids. The mouth opening is guarded by 

 four toothlike formations arranged in the shape of a rectangle. They 

 are somewhat more strongly developed than in the type species. The 

 mouth cavity is funnel shaped, leading to the elongated club-shaped 

 esophagus, which is surrounded by the nerve ring about SOOjm 

 posterior to the head. 



Male 9 to 10.5 mm. long with a maximum width of 210/i, to 220/i. 

 Esophagus 1 mm. long, being, therefore, about one-tenth of the length 

 of the body. The strongly striated bursa is trilobed, the dorsal lobe 

 being extremely small, while the free edges of the well developed 

 lateral lobes are folded over the ventral surface. The dorsal ray is 

 stout, about T5/X long, dividing close to the distal extremity to form 

 two short branches, each of which bifurcates again in a thinner 

 median and a thicker outer branch, both with the tip approximately 

 on the border of the dorsal lobe. The externo-dorsal rays are stout, 

 about 100/A long, terminating with their rounded distal ends some 

 distance from the edge of the bursa. The lateral rays have a com- 

 mon stem ; the posterior-laterals and medio-laterals, running parallel, 

 terminate in fine points on the bursal margin, while the blunt ex- 

 tremities of the externo-laterals are slightly bent forward. The 

 slightly curved ventral rays originate from a common base and are 

 pointed distally ; the ventro-ventrals appear more slender and shorter 

 than the latero-ventrals. The posterior lip of the cloaca bears a pair 

 of sessile papillae. The prebursal papillae are very poorly developed. 

 The spicules have a length of about 180/x to 200/a, dividing distally to 

 form one dorsal and two subventral branches. 



