ART. 7 



CESTODE PAEASITES OF BIRDS LINTON 



19 



series of transverse sections. There are two layers of longitudinal 

 muscles, the outer with the more numerous bundles. The inner 

 circle, as seen in transverse sections, is not quite continuous, one or 

 two bundles being lacking in the vicinity of the excretory vessels. 



In a strobile 8 mm. in length rudiments of genitalia could be seen 

 0.05 mm. back of the scolex; the full complement of testes was at- 

 tained at a distance of a little less than 2 mm. from the scolex; the 

 adult ovary was noted at about 3 mm. from the scolex ; and at about 

 the middle of the strobile, that is about 4 mm. from the scolex, the 

 uterus appeared. At first the uterus consisted of an axial mass of 

 ova, whose contours could not be made out in the whole mounts. 

 From the axial mass lateral diverticula appeared in succeeding 

 proglottides, the uterus soon becoming profoundly lobed. In the 

 last two millimeters of the strobile, comprising about 12 proglottides, 

 the uterus was lobed as shown in figure 49. 



The ova were rather too closely packed in the uterus of the whole 

 mounts to admit of satisfactory measurement. They appear to have 

 two membranous shells, the diameter of the outer being from 0.024 

 to 0.03 mm. The following note was made on living material col- 

 lected July 9, 1913 : Shells of ova thin and at first collapsed ; when 

 placed in fresh water the outer shell became turgid; diameter of 

 outer shell 0.066 mm., of inner shell 0.033, of onchosphere, containing 

 a six-hooked embryo, 0.019. 



Most of the strobiles in my collection are small, about 8 mm. in 

 length, although a few are longer (see below) and are in close agree- 

 ment with Clerc's description of the species.^ 



Measurements of strobiles mounted in balsam are as follows : 



Length 



Diameter of scolex 



Length of scolex 



Diameter of suckers 



Diameter of rostellum 



Length of rostellum 



Length of larger hooks 



Length of smaller hooks 



Length of posterior segments.. 

 Breadth of posterior segments. 



Mm. 



8.00 

 . 12 

 .06 

 .05 



21 



42 



Mm. 

 15.00 

 . 14 

 .08 

 .05 

 .05 

 .024 

 .033 

 .018 

 .30 

 .46 



Mm. 



23. 00 



. 14 



.07 



. 06 



.35 

 .46 



RECORD OF COLLECTIONS 



From Butorides virescens : 

 1906, June 20.— Eighteen. 



1912, August 14. — Nine from one of two herons, maximum 

 length about 12 mm. 



(U.S.N.M., Helm Coll. 7866.) 



1 Centralbl. Bakter, Parasit., vol. 32, pp. 714-715, figs. 3 and 4. 



