MORPHOLOGY OF CESTODES FROM POULTRY 39 



This form is one of the most common chicken tapeworms 

 and is the most easily recognized. It can be identified by the head 

 with its broad, flat rostellum which shows up very prominently; 

 the width of the most anterior segments is usually equal to or 

 greater than the width of the head, and the eggs are distributed 

 in individual egg capsules in mature proglottids. 



4. Hymenolepis carioca (Magalhaes 1898) Ransom 1902 



Diagnosis: Length 30 to 80 mm. Breadth at neck 75 to 150/a, 

 at posterior end 0.5 to 0.7 mm. Segments three to five times or 

 more broader than long throughout strobila. Head (Fig. 26) 

 flattened dorso-ventrally, 140 to 160iLi long, 150 to 215/x. wide and 

 100 to 140^ thick. Suckers shallow, 70 to 90/x in diameter, un- 

 armed. Rostellum unarmed; in retracted position 25 to 40/x in 

 diameter and 90 to 100/x in length, with small pocket opening to 

 exterior in anterior position. Unsegmented neck portion of strobila 

 0.6 to 1.5 mm. long. Genital pores almost entirely unilateral, a 

 single pore being located in each segment slightly in front of middle 

 of right-hand margin. 



Male Reproductive Organs: Testicles three in number, nor- 

 mally two on left and one on right of median line. On dorsal 

 side of inner end of cirrus pouch vas deferens is swollen into 

 prominent seminal vesicle (Fig. 18, sv) which may attain a size 

 of 70 by 50jLt. Cirrus pouch (Fig. 18, cp) in sexually mature 

 segments 120 to 175^^ long by 15 to 18/^ in diameter ; almost cylindri- 

 cal, slightly curved toward ventral surface of segment; on outer 

 surface about 20 longitudinal muscle bands, 2 to 3/x in thickness, 

 very prominent in cross section; vas deferens enlarged within 

 cirrus pouch to form small seminal reservoir occupying proximal 

 two-thirds of pouch ; distal third of portion of vas deferens within 

 pouch very slender, about 1/x in diameter and functions as cirrus. 

 Genital cloaca 12 to 36/i deep. 



Female Reproductive Organs: Opening of vagina in floor of 

 genital cloaca, ventral and posterior to cirrus opening. First por- 

 tion of vagina very narrow, V in diameter. Small vaginal sphinc- 

 ter 8 to 10/x from vaginal opening. On inner side of sphincter 

 vagina gradually increases in diameter, and in sexually mature 



