2 PROCEEDINGS OF THE NATIONAL MUSEUM, vol. 65. 



In any case, irrespective of the possibility of the occurrence of the 

 species, which Looss calls TJ. criniformis^ in dogs, there is unques- 

 tionably another species common in European dogs, which Railliet 

 has called Uncinm'ia sfenocephala, that is distinctly different from U. 

 criniformis of Meles taxus. Furthermore ZJncinaria stenocephala in- 

 stead of being the same species as U. criniformis is in reality the same 

 as U. polaris. Not only does Railliet's description of U. stenocephala 

 in certain important respects (size of worms, maximum length of 

 spicules, and tridigitation of terminal branches of doreal ray of 

 bui'sa) agree with what is found in the specimens of Uncinaria po- 

 laris (U. S. N. M., 3250) and differing in these respects from what is 

 found in U. criniformis^ but specimens of Uncinaria from dogs in 

 various parts of Europe corresponding to Railliet's description of 

 Uncinaria stenocephala agree among themselves and with U. polaris 

 and differ from U. crinifonnis as described by Looss and as shown 

 by several lots of specimens from Meles taxus. For European speci- 

 mens of U. stenocephala from dogs and TJ . criniformis from Meles 

 taxus to compare with V . polaris I am indebted to Prof. P. Ciurea^ 

 Bucurest, Rumania; Prof. A. Heniy, Alfort, France; Prof. J. E. W. 

 Ihle, Utrecht, Holland, and Prof. T. Pintner, Vienna, Austria. 



Readily recognizable differences between the two species involved, 

 Uncinaria criniformis and U. stenocephala.^ including its synonym, Z7. 

 polaris, are shown in the following brief descriptions. The descrip- 

 tions are not intended to be complete but refer specially to characters 

 that seem useful for diagnostic purposes. 



UNCINARIA CRINIFORMIS (Goeze. 1782). 



Specific diagnosis. — Uncinaria: Male about 5.5 (5.3 to 5.9) mm., 

 female about 7.5 (6.8 to 8.2) mm. long. The ventral wall of the 

 mouth capsule when viewed in optical section from the side is only 

 slightly curved as a rule (fig. 9). The boundary line between the 

 thicker ventral portion and the thinner dorsal portion of the mouth 

 capsule wall (side view) turns forward along the ventral side of the 

 cord of tissue which terminates in the lateral cephalic papilla, and 

 meets the anterior border of the mouth capsule almost at right angles 

 (fig. 9, x). Esophagus of male about 0.55 mm. long, of female about 

 0.6 mm. long. Lateral lobes of male bursa only a little more than 

 semicircular in shape. Medio-lateral ray slightly thicker than the 

 postero-lateral ray and much thicker than the externo-lateral ray 

 (fig. 10). Dorsal ray bifurcated distally, each branch bidigitate 

 (fig. 11). Spicules 0.46 to 0.63 mm. long with rounded membranous 

 tips. Tail of female 125 to 135 [x long; tip of tail into which the 

 caudal bristle is inserted almost ogival in outline (fig. 12). Vulva 

 4.5 to 5.5 mm. from anterior end of body. 



