PROCEEDINGS OF THE NATIONAL MUSEUM. 103 
In the longest specimen the last segments were 0.5 millimeter in 
length and 1.5 millimeters in breadth. The length of the first distinet 
segments was 0.5 and the breadth 0.2 millimeter. The anterior end for 
about 8 millimeters was attenuate and without evident segments. The 
first evident segments were a little more than twice as long as wide. 
‘The reproductive apertures are all on one margin, about the middle of 
the segments, somewhat prominent with thickened, protrading borders. 
The color of the alcoholic specimens is yellowish white. Segments 
somewhat like those from Colymbus in outline but not so thick, and 
rather more regular; strobile in general more delicate. 
T. fusus Krabbe is suggested by these fragments. 
Ill. Fragments of Tenia from Larus sp. Museum No. 4932. Col- 
lector’s No. 975 (Figs. 57, 58). Mr. Jouy’s note on this lot is as fol- 
lows: “975. Parasitic worms (tapeworms) from the intestines of 
gull Larus (Chroicocephalus) sp. 8. The throat and stomach of this 
specimen also clean and empty.” 
This lot consists of several fragments belonging to about three stro- 
biles. The longest fragment measures 18 millimeters in length. The 
aggregate length of the fragments is about 140 millimeters. Anterior 
| segments funnel shape, succeeding segments much crowded, and much 
broader than long; posterior segments squarish or rounded, separat- 
| ing easily from the strobile, about 1 millimeter in length and 0.6 
millimeter in breadth. Reproductive apertures alternate and appar- 
ently regulariy so; apertures near anterior end of segment. Ova 
spherical with thin walls, containingembryos. Diameterofexternal shell, 
0.05 millimeter; diameter of embryo, 0.03 millimeter; length of spines, 
0.01 millimeter. Some of the ova have thin, somewhat wrinkled shells ; 
/ some also have what appear to be small curved hooks over the surface 
(Fig. 58). The specific determination of these fragments is not cer- 
tain. In some particulars it agrees closely with 7. larina Krabbe. 
All of these Guaymas fragments contained numerous small granular 
| bodies, the largest of which measured 0.025 millimeter in greatest 
| diameter, although usually smaller than that. In oil of cloves these 
|, particles frequently showed a concentric structure. They dissolve in 
|| acetic acid; but with difficulty. Brisk effervescence was not obtained 
even with heated hydrochloric acid. This character is in marked 
| contrast with the behavior of the calcareous particles in the Yellowstone 
_Lake specimens, where brisk effervescence followed treatment with 
| acetic acid. 
| Tznia porosa Rudolphi. 
(PI. vit, Figs. 59-71.) 
Rudolphi, Entoz. Hist. 111, 190, Pl. x, 1; Synopsis 168 and 529, Pl. 1, 7,8. Dujardin, 
Hist. Nat. des Helm, 561. Diesing, Syst. Helm. 1, 546; Sitzb. xu, 610; Sitzb. 
XLix, 415; Krabbe, Bitrag til Kund. orn Fugl. Biend., 260, 261, Pl. 1, 10-13. 
» Head subglobose, bothria somewhat circular with a thick border ; pro- 
| boscis eylindrical, armed with from twelve to fifteen hooks, which are 
