T^NIOID CESTODES OF NORTH AMERICAN BIRDS. 57 



47. Division of stroblla into segments well marljed ; female glands toward pore 



side of segment; genital canals pass between the excretory vessels and 

 ventral of the nerve ; genital pores irregularly alternate. 



Laterotwnia, p. 82. 

 Strobila small, division into segments not v^^ell marked; scolex large with 

 small rostellnm ; reproductive glands very small ; ovary and yolk gland 

 toward pore side of segment ; genital pores irregularly alternate. 



Parvirostritm, p. SI. 



48. Genital canals pass between the longitudinal excretory vessels and dorsal 



of the nerve; genital pores irregularly alternate; strobila usually with 



numerous segments; uterus sac-like Anomotwnia, p. 77. 



Genital canals pass dorsal of the longitudinal vessels and nerve; strobila 

 with few segments (less than 30) ; genital pores regularly alternate; 

 uterus much lobulated ; outer shell of egg with tubular prolongation at 

 each pole terminating in a globular expansion Liga, p. 80. 



49. A single genital pore in each segment 50. 



Two genital pores in each segment, one on each side 67. 



.50. Para-uterine organs absent __- 51. 



Para-uterine organs present . 62. 



51. Uterus persistent 52. 



Uterus not persistent, breaks down into numerous egg capsules, each con- 

 taining one or more eggs 60. 



52. Three testicles in each segment ; rostellnm present but rudimentary and 



unai'med . Hymenolepis s. str., p. 90. 



Testicles more than three in each segment 53. 



53. Uterus with median stem and lateral bi'anches; rostellnm rudimentary and 



unarmed, or lacking 54. 



Uterus sac-like or reticular, without median stem ; rostellnm lacking 55. 



54. Female glands in posterior median portion of segment ; testicles scattered 



throughout the medullary parenchyma except the posterior median por- 

 tion ; egg with a thin outer membrane, and thick brown radially striated 

 inner shell; rostellnm present but unarmed and rudimentary-Tcenia, p. 100. 

 Female glands in anterior portion of segment ; testicles in posterior portion ; 

 egg with thin transparent shells; rostellnm absent C atenotcenia, p. 84. 



55. A distinct pedunculated prostatic gland near ventral excretory vessel on 



pore side of median line ; egg with pyriform apparatus, the horns of 



which are rather short; adults in mammals Andrya, p. 63. 



Pedunculated prostatic gland absent 56. 



56. Eggs with pyriform apparatus 57. 



Eggs without pyriform apparatus 59. 



57. Uterus a transversely elongated sac with outpocketings anteriorly and pos- 



teriorly 58. 



Extreme lateral portions of uterus sac-like, remainder a complicated system 

 of irregular lacunse; testicles near the posterior border of segment ex- 

 tending from the excretory vessels of one side to those of the other; 

 adults in mammals Schizotcenia, p. 64. 



58. Testicles in anterior portion of segment extending entirely across the median 



field as far as the excretory vessels; adults in birds and mammals. 



BerUella, p. 62. 

 Testicles in median field toward side of segment opposite genital pore; fe- 

 male glands in median field toward pore side ; adults in mammals. 



AnojJlocephala, p. 62. 



