20 PROCEEDINGS OF THE NATIONAL MUSEUM vol.70 



1913, July 9, — Five, no scoleces, maximum length about 12 mm. 



1913, August 14. — A few fragments of strobiles, no scoleces. 



1914, July 28. — Numerous, length of largest less than 10 mm. 

 1916, July 20. — Numerous, 100 or more, from three herons, most 



of them about 5 mm. in length scoleces present in a few. 



CHOANOTAENIA PARINA (Dujardin) 

 Figures 52-53 



Three scoleces, and fragments of strobiles aggregating about 200 

 mm. in length, agree with descriptions of this species. Since there 

 appear to be four strobiles represented in the lot, an average length 

 of 50 mm. is indicated, which is the length recorded by Clerc for this 

 species. The maximum breadth is about 0.8, which is in agree- 

 ment with Clerc's record. A scolex with rostellum retracted meas- 

 ures 0.24 in breadth; another with rostellum exserted, and some- 

 what distorted, measures 0.16 in breadth; the diameter of a sucker 

 is about 0.10. There are 20 hooks in a single circle, about 0.015 in 

 length. There is a distinct unsegmented, or neck, portion of the stro- 

 bile. The proglottides, at first broader than long, lengthen gradu- 

 ally and ultimately are longer than broad. There is, however, con- 

 siderable variety in the shape of the proglottides, and the different 

 contraction shapes impart much variety in the apparent disposition 

 of the genitalia. The genital pores are irregularly alternate, and 

 open near the anterior third of the margin of the proglottis. The 

 general plan of the genitalia is shown in figure 53. The ventral ex- 

 cretory vessels are conspicuous in most of the proglottides except 

 those which are filled with ova. A typical ovum measured 0.045 by 

 0.033; diameter of onchosphere 0.03; length of onchosphere hooks 

 0.018. 



From Passer domesticus^ August 30, 1923. 



(U.S.N.M., Helm. Coll. 7867.) 



CHOANOTAENIA RANSOMI. new species 

 Figures 54-68 



The taenioids referred to this species were collected from several 

 species of gulls, on many widely separated dates, mainly by Vinal N. 

 Edwards, and all from the Woods Hole region ; also a few taenioids 

 from the loon appear to belong here. 



They present a great variety of contraction shapes, but there do 

 not appear to be differences sufficient to justify their assignment to 

 different species. 



Scolex. — There is little difference in the size and shape of the 

 scoleces; in general it is broader than long. Thus, an average of 



