a!:t. 7 CESTODE PARASITES OF BIRDS LINTON 53 



VALIPORA, new genus 



Dipylidmiae : 



Rostellum armed with a single crown of hooks, 0.01 to 0.03 mm. 

 in length, with long dorsal and short ventral roots. Genital pores 

 unilateral; genital cloaca with strong muscular walls. Genital ducts 

 pass between the longitudinal excretory vessels. Testes 12 to 25, 

 or more, posterior or lateral to ovary. Uterus saclike, lobed, but 

 filling the medullary space in ripe segments. 



The cestodes here placed have many characters which ally them to 

 the genera Laterifoi^s Fuhrmann, and Monopylidium Fuhrmann. 



Type of genus. — Valipora 7nutdbilis. 



VALIPORA MUTABILIS. new species 

 Figures 174-181 



The cestodes from the night heron, here considered, appear to 

 belong to the same species. There is considerable variation, particu- 

 larly in the form of the ovary and uterus in proglottides of different 

 stages of development and in the shape of the proglottides them- 

 selves, but in some of the longer strobiles there is as great variation 

 in these respects in a single strobile as Avas observed in different 

 strobiles. 



Scolex. — The mounted specimens exhibit a variety of contraction 

 shapes, and there is considerable difference in dimensions. The fol- 

 lowing dimensions are averages of five scoleces: Length 0.11 mm., 

 breadth 0.18; sucker, length 0.10, breadth 0.075. The rostellum was 

 retracted in all cases, and the number of hooks was difficult to deter- 

 mine. There appear to be 10; length 0.03 mm. The hooks are 

 slender, straight, and rather abruptly recurved at the tip. 



Strobile. — Measurements of the living worm gave a maximum 

 length of about 20 mm. A few strobiles which had been placed for 

 a short time in fresh water extended to more than twice that length. 

 The longest mounted specimen measures approximately 35 mm. in 

 length. In normal strobiles the breadth of the neck is about 0.06. 

 Segments begin near the scolex. At first much broader than long, the 

 proglottides increase slowly in length and breadth, but remain much 

 broader than long. The posterior edge overlaps the succeeding seg- 

 ment, so that the cirrus-pouch of the succeeding segment is nearly or 

 quite covered by the overlapping border of the preceding segment. 

 In a strobile measuring about 15 mm. in length, at a point 2 mm, 

 back of the scolex, the segments are 0.06 in length and 0.14 in 

 breadth; at the middle of the strobile they are 0.10 in length and 0.18 

 in breadth; near the posterior end the length is 0.11, and the breadth 

 0.56; the posterior two or three segments were 0.21 in length and 

 0.54 in breadth. These proglottides were adult but not ripe. Length 



