PS Dy cas ° a es Paras SS 
= ~ ~ 
= ri Ee 
104 AVIAN ENTQZOA—LINTON, = : 
0.12 millimeter in length and straightish; neck short; first segments 
very short, subsequently variously longer and narrower, often infundi 
buliform; posterior segments on longest strobiles, squarish and trans- 
versely wrinkled; genital apertures irregularly alternate, cirrus short, 
opening near anterior edge of margin and directed forward ; ova witha 
double envelope; length of embryonic hooks, 0.35 millimeter. Largest 
specimen measured while living, 120 millimeters in length and 2.5 milli. | 
meters in greatest breadth. Greatest recorded length hitherto, 100° 
millimeters. 
Hasirat: Larus californicus, intestine, Yellowstone Lake, on differ- 
ent dates in August, 1890. 
I refer to this species several Tenia, which, while presenting some 
differences among themselves that are difficult to reconcile with each 
other, do not, at least with the material at hand, appear to me to justiyg 
their separation into distinct species. 
But one specimen with ripe proglottides was found. This was asso- 
ciated with several specimens of 7’. filum collected on August 2, 1890, 
and had the following dimensions and characteristics : 
Millimeters. 
Diptera ss cece dans faves pe echep we hee tees more tees 110. 00 
Diameter of head....--. --- HHECOOON Saco and: 50 See es eSae . 46 
héenathiothewd:scsescesses Sas see ae ee Sa eee aeeiee . 30 
ene thio LpNOVOSCIat ss cme tees eaeeie es eee eee . 38 
Diameteriot proboscis 22--ee acme See eee aaa siti . 
Diameter\of icrown of hooks: sss5- o=--1s-s= ss esse eee “9 
en ei hrothoo ksi acrese syste tate area etal alee ane ee 12 
Diameterofneck = 25-5 bese seine centeclsio eee teeta eee . 35 
“Length of anterior segments ..... ~~. ..--2-te---0 sseees . 20 
Breadth of ‘anterior segments)... ---. . 26 0c oe eee ee 25 
Length of posterior segments ~.. -...... 2. .ssinse-cees em | euCe 
Breadth of posterior sesments.-:-..-----5<.5---- =s---- 2.50 
The above dimensions are from measurements of an alcoholic speci- 
men. The living worm measured 120 millimeters in length. The — 
diameter of the proboscis immediately behind the hooks and at base 
was 0.09 millimeter ; at apex and in middle, 0.11 miltimeter. The pos- 
terior segments became dilated in alcohol. They were subglobose, 
being swollen with the contained embryos. The hooks on the pro- 
boscis were in a single circle and were fourteen in number. The com- 
plete set is probably fifteen. These hooks are uniform in size and 
shape, and are exactly 0.12 millimeter in length. The anterior seg- 
ments are somewhat funnel shape, preceded, however, by very short 
beginning segments like transverse wrinkles; the median segments are 
somewhat rectangular, broader than long, and increasing in breadth 
toward the posterior end. Toward the posterior end of the strobile 
the segments have one or two wrinkles at the margin. The reproduc- 
tive apertures are marginal near the anterior end of the segments and 
irregularly alternate, although often for a series of a dozen or more seg- 
ments irregularly alternate. The cirri are short, smooth, and directed 
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