26 PROCEEDINGS OF THE NATIONAL MUSEUM vol.70 



1912, November 15. — Seven gulls examined; 35 strobiles, and 

 fragments from two birds ; longest strobile noted 72 mm, 



1912, November 20. — Four gulls examined; seven strobiles, tAvo 

 with scoleces, from one bird. 



1912, December 21. — Eight gulls examined; four strobiles with 

 scoleces, and a few fragments. 



1913, April 3. — Eight gulls examined; nine strobiles with 

 scoleces, and eight fragments from two birds ; maximum length 

 about 62 mm. 



Ga/via invmer: 



1915, August 11.— Few. 

 This species from the loon appears to be identical with that from 

 the gulls, and is therefore recorded under C. ransomi. The diameter 

 of scoleces in balsam is from 0.35 to 41 mm. ; diameter of sucker about 

 0.18; length of hooks about 0.032. The arrangement of the hooks of 

 the rostellum, as in those from gulls, is difficult to interpret. In 

 most views there appears to be a single circle of hooks, but in favor- 

 able position they are seen to be as shown in figure 59 ; that is, in two 

 very closely placed circles. The hooks are aU of practically the same 

 length. 



CHOANOTAENIA, species 



Figures 69, 70 



A scoiex found on a slide along with several strobiles of Hyvieno- 

 lepis ductilis from Larus argentatus diilers from other species in 

 the collection. The size and shape of the hooks suggest G. porosa, 

 although the number appears to be 12, instead of 14, the number 

 given for that species. 



(U.S.N.M., Helm. Coll. 7870.) 



The scoiex is broader than long, and the suckers have strong, 

 muscular borders. The rostellum is retracted but is clearly shown. 

 It is slender wdth thickish, muscular walls, and appears, as it lies 

 in its sheath, as a rigid, pestle-shaped structure, with a bulbous 

 enlargement at the anterior end, whose diameter is about equal to the 

 length of the hooks. From this anterior hook-bearing end it tapers 

 to a bluntly rounded posterior end. This slender, tapering portion, 

 beginning at the level of the anterior borders of the suckers, extends 

 for a distance equal to half of its length back of the posterior bor- 

 ders of the suckers. Breadth of scoiex 0.40 mm. ; diameter of sucker 

 0.18; length of hooks 0.105; length of rostellum 0.42; distance to 

 first segments 0.28 ; length of first segments 0.01 ; breadth 0.28. The 

 neck is of about the same breadth as the scoiex. About 0.25 mm. 

 behind the scoiex the strobile narrows, and the last segments, which 

 are 0.84 mm. back of the scoiex, have a length of 0.07 and a breadth 

 of 0.25. 



