320 PARASITIC WORMS. 



in length. The specimens are in a somewhat contracted 

 condition, so that tlie neck appears short. The segments are 

 very nnmerons, and for the most part are broader than long 

 (much broader in contracted specimens). The gravid seg- 

 ments, however, become square, and finally, in some speci- 

 mens, slightly longer than broad. The subcuticular and mus- 

 cular layers are well-developed. The medullary parenchyme 

 occupies not much more than one-third of the width of the 

 ■strobila. The genital pores are unilateral (on the right side), 

 and situated a little in front of the middle of the lateral borders 

 of the segments. There is a small muscular genital atrium. 

 The cirrus-sac is relatively large, measuring about 0.16 mm. 

 in length and 0.055 mm. in greatest thickness. It curves 

 forward from the pore, its inner end nearly reaching the an- 

 terior border of the segment. The cirrus is very muscular. 

 The ovary is distinctly divided into two lateral masses, which 

 form a triangle with the large yolk-gland, situated posteriorly. 

 The testes are relatively large, apparently only five in number, 

 immediately surrounding the female glands behind and at 

 the sides, but more dorsal in position. The uterus, at first a 

 sac, breaks down into egg-capsules, each of which contains 

 about eight eggs. The capsules are confined to the space 

 between the wide and conspicuous longitudinal excretory 

 vessels. 



This species differs from the great majority of forms in the 

 Subgenus Eansomia in its small number of testes. There are, 

 however, certain species resembling it in this respect. R. (R.) 

 niutabilis Eiither has, according to Fuhrmann (1920), only 

 one testis per segment ; cacatuina (Johnston, 1911) has four or 

 five; oligorchida (Fuhrm., 1911) has five or six; and paucites- 

 ticulata (Fuhrm., 1909) has six or seven. Of the three last- 

 mentioned forms, cacatuina and paucitesticulata show a very 

 close resemblance to the species just described, but both are 

 evidently smaller forms, and nearly all the measurements 

 given for them are considerably less than the corresponding 

 figures for R. calyptomenae. In R. paucitesticulata the 

 rostellar hooks are larger (0.012—0.014 mm.), and the cirrus-sac 

 considerably smaller (0.07-0.088 mm. long). In addition, 

 it may be mentioned tliat R. paucitesticulata tfccurs in a 

 pigeon, while cacatuina and oligorchida occur in Psittaciform 

 birds. The writer is unable to find records of any Cestodes 

 from birds of the group (Eurylaemidae) to which the present 

 host belongs. 



