[17] ENTOZOA OF MARINE FISHES OF NEW ENGLAND. 469 
It differs from O. versatile, however, in being much smaller, and in 
the proportions of the segments. In O. versatile the segments are 
square, while in O. angustwm all the segments are long and narrow. 
The following measurements were made from mounted specimens : 




Dimensions. | No.1. | No.2. } No.3: 
4 
| mm. mm. mm. 
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Breadth of BOveIOM Mt Ost PAG sees cee as sale ea laeaalalate|afainitidiatmola\ela imma Pe ONS2s [esas Baral meets 
MBMOUMEO ENGL NOAT HOAG fascia canals | cae cia ane 2 wale = wie Sta alain wralale is aiolainiate | QE y | Soe Noes ee ese 
EESTI METIA OK eee co as oh sae acen caacalel Ames coawaacg east cjesehwlisinces s ees DOO) eee alae eee 
Pete tmnOStOLiGr SGOMEND, «co dacc cs sascdaduelenisceeisdsee tale ccinews scech spices | \ 2.20 |! %:2.:00;) 2. 46 
Rete OSUCLION SG2MON tt saac a aoc ematae sau tas cacee ciceceelone cis densme | 0.44) 0.28 | 0. 54 
\ | 


The anterior supplemental disk (auxiliary acetabulum) is small and cir- 
cular and is quite manifest. Imtst confess, however, that the identifica- 
tion of the other was not wholly satisfactory. An oval disk was distin- 
guished ina few. In some heads stained with carmine, eosin, and hema- 
toxylon, respectively, they cannot be distinguished. At about the ante- 
rior third the face of each bothrium, in the stained specimens, is crossed 
by a curved fibrous band which is concave in front. This band lies in 
the tissue of the bothrium and is not raised on the surface. It seems to 
be connected with another band lying farther back in the bothrium and 
deeper in its substance. If they are connected they probably make the 
oval border of the second disk. If one is to judge from the specimens in 
this lot—abonui fifteen in number—the secondary disk in the center of the 
bothria is an extreme doubtful character. It is plainly different in its 
nature from the anterior disk which was differentiated from the adjacent 
tissue cleccly, both in unstained and stained specimens. The fine trans- 
verse strive on the neck, which may be distinguished also on the mature 
proglottides, are a more characteristic feature of this worm than the 
second disk (auxiliary acetabulum). 
The genital organs open nearly opposite the anterior fourth of the 
-_proglottis, on the margin. 
' The vagina can be traced from the posterior end of the segment, 
where it originates as a coiled tube, lying between the two marginally 
placed ovaries. It lies along the central line of the segment, until a 
short distance in front of a point opposite the vaginal opening, where 
it turns, forming a crook-shaped curve, and opens in front of the penis. 
The latter organ and the testis lie in the curve of the crook. 
Habitat—Dusky Shark (Carcharias obscurus), in spiral intestine. 
Wood’s Holl, Mass., August, 1854. 
CROSSOBOTHRIUM,* gen. noy. 
Body articulated, slender, flattened, subquadrate; neck short or 
none ; bothria four, opposite, pediccled, unarmed, each provided with 

* Kp0660i = = border, fringe. 
