10 PEOCEEDINGS OF THE NATIONAL MUSEUM vou 70 



Lams argentoitus: 



This species was collected at Woods Hole on many dates in all 

 except two months of the year. 



January. — On seven dates in three different years; few found 

 on any date; in most cases the scoleces were missing; maxi- 

 mum length 40 mm. 



February. — On eight dates in four different years; largest num- 

 ber found on any date 30 ; maximum length 100 mm. On one 

 date the record is " many, 15 with scoleces." 



March. — On one date; 3 fragments; maximum length 85 mm.; 

 no scoleces. 



April. — On six dates in four different years; largest number 

 with scoleces found on any date 7; maximum length 220 mm. 



May. — On three dates in two different years; largest number 

 found on any date 18; maximum length 150 mm., maximum 

 breadth 3. 



July. — One date; six strobiles with scoleces, and about 12 

 scoleces with only anterior portion of strobile attached ; numer- 

 ous strobiles without scoleces. 



September. — One date; eight, four with scoleces; many frag- 

 ments. 



October. — One date; three strobiles, no scoleces. 



November. — On four dates in three different years; one on each 

 of three of the dates. On the other date the record is : " Many 

 strobiles without scoleces; 2 scoleces; breadth of strobile 2 

 mm."; maximum length 160. 



December. — On four dates in three different years; greatest 

 number on any date 4; maximum length 70 mm., breadth 2. 



TETRABOTHRIUS HETEROCLITUS (Diesing) 



Figures 14-22 



Cestodes of this genus, collected from three species of shearwater, 

 and the night heron, as was the case in cestodes of the same genus 

 from gulls and divers, exhibit much variability in size of strobiles 

 and in the shape of the proglottides. Some diversity also exists in 

 the scoleces. 



Scolex. — Bothria oval-elliptical, with relatively thick, muscular 

 borders; appendage appearing rather weak, but in well-preserved 

 specimens seen to be fairly well developed. The majority of the 

 scoleces in balsam have a length and breadth of about 0.35 mm. 

 Thus 22 scoleces averaged 0.37 in length and breadth; 12 of the 22 

 measured 0.35 by 0.35. A few scoleces were seen which were larger; 

 length 0.75, breadth 0.72, and, one much smaller, length and 

 breadth 0.21. 



