a eS # * hen 
i . m ‘ % > 
vem.’ ] +. PROCEEDINGS OF THE NATIONAL MUSEUM. (105 
forward. The embryos are well developed in the ripe segments, are en- 
closed in a double envelope, and their hooks are of three sorts (Fig. 66). 
Two of the hooks are broader than the other four, and two of the re- 
- maining feur are more curved than the others. There is no material 
_ difference in length, however, each measuring about 0.035 millimeter. 
Two specimens, 25 and 10 millimeters in length, respectively, and two 
fragments 6 and 8 millimeters in length, were obtained from another 
gull. The number of hooks in the larger was about fifteen, in the smaller 
- twelve. The hooks agree in shape and size with those of the first 
specimen. 
No reproductive apertures were seen in the smaller specimen. In 
the other they appeared at first to be situated along one margin, but 
upon closer examination were found to be irregularly alternate, with a 
tendency for several successive segments to have the reproductive 
_ apertures on the same margin. Cirrus short, conical, as seen, 0.17 milli- 
- meter in length, 0.05 millimeter in diameter at base, and 0.02 millimeter 
~ in diameter at apex. 
In all of the foregoing there were numerous minute calcareous bodies, 
showing under proper optical conditions a concentric structure, and 
evolving carbon dioxide briskly when treated with acetic acid. These 
were particularly abundant in the two smaller specimens. They are 
more abundant in the median and posterior segments, few appearing 
in the anterior portion of the strobile. 
Variety «. (Figs. 67-71.)—Three specimens from a gull captured 
August 10, 1890, are referred to this species, but on account of certain 
constant characters of difference they are given a special place. 
The specimens measured 15, 17, and 21 millimeters in length respect- 
ively; breadth near posterior end 1 millimeter. Head broad, com- 
pressed, 0.55 millimeter broad and 0.3 millimeter thick ; diameter of neck 
0.3 millimeter, in onethe diameter immediately behind the head was 0.4 
millimeter, and one millimeter back of head 0.32 millimeter. The hooks 
are exactly twelve in number and measure 0.12 millimeter in length. 
They agree in shape and size with those of the other specimens. 
The strobiles are all young and complete—that is, they have not 
lost any segments. They are rather plump, increasing in breadth uni- 
formly from the neck to near the posterior end. The strobile thus has 
somewhat the shape of a club, nearly cylindrical in middle portion, 
but compressed elsewhere. The reproductive apertures are irregularly 
alternate, with a tendency to be regularly alternate for several suc- 
cessive segments. The apertures are near the anterior edge of the 
segments at the margins. A series of sections was made of several of 
the posterior segments, from which it was ascertained that the cirri, 
which are all retracted, are smooth and agree with those of the others 
inshape. Caleareous bodies are not so numerous as in the other speci- 
mens. The male reproductive organs were well developed, consisting 
of a voluminous vas deferens, large testicular lobes, containing sperm- 
