NO. 2258 TAEXIOID CESTODES OF DOGS AND CATS— HALL. 



33 



mately parallel, usually quite distinctly wavy in outline but occa- 

 sionally almost straight, and usually with a more or less well-marked 

 convexity on the dorsal border near the union with the guard, the 

 union, as a result, forming a more or less obtuse angle, while the 

 other end of the convexity frequently terminates in a notch in the 

 dorsal margin of the handle; the guard is at right angles to the 

 blade and is roughly conical to elongate cordiform in lateral view, 

 the maximum thickness being a short distance from the point of 

 union and so forming a proximal neck. The small hooks are 96 to 

 128 \). long. The blade docs not present a prominent conca\'ity on its 

 ventral surface, but it makes a sharp curve, amounting at times al- 

 most to a bend, and then straightens out with the point past the ex- 

 tended longitudinal axis of the handle; the handle is long, narrow, 

 and tapering with a marked 

 tendency, unusual in dog tape- 

 worms, to turn ventrally at 

 the distal extremity, and with 

 the dorsal and ventral mar- 

 gins rather straight or onlv 

 slightly wavy; the guard i:^ 

 united to the handle at an 

 obtuse angle and is of approx- 

 imately the same shape as that 

 of the large hook, the guard 

 at times showing a slight 

 median ventral groove. The 

 suckers are 270 to 320 a in 

 diainetcr and are set on at the 

 corners of the oblong head. 

 The neck is distinct, narrower 

 than the head, 650 to 900 :j, 

 wide, varying in length according to the state of contraction, a speci- 

 men in a state of moderate contraction having a neck about 600 [k long 

 from the posterior border of the suckers to the first distinct segmenta- 

 tion. The strobila i?< 45 to 110 cm. long, with a maximum width of 4 

 to 8.5 mm,, and has a tendency to twist in the form of a spiral. The 

 segments have convex lateral borders. Immature and mature seg 

 ments are wider than long; gravid segments are longer than wide. 

 Mature segments are 1.9 to 3.5 mm. long and 5.5 to 6.5 mm. wide 

 Gravid segments attain a maximum length of 15 mm., the width 

 varying with the state of contraction, from 3 to 5.5 nun. The genital 

 papillae are very prominent, the entire lateral border on the pore 

 side being much more sharply convex than on the aporal side. They 

 are situated in the middle of the segment and in gravid segments 

 may attain a diameter of over 1 mm. and an elevation of 750 [i 

 62055— 20— Proc.N.M. Vol.55 4 



Fig. 37.— Taenia ovis. Large and small hooks. 



