780 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [62] 



,010 mm , with diameter at base .003 mm ; in another case, length of spines 

 .022 111 " 1 , length of basal part .002'™, diameter .0027 to .003G: i,m . 



The vagina is a narrow, much convoluted tube which originates be- 

 tween the two lobes of the ovary, in the posterior part of the segment. 

 It follows the median line to a point on a level with the cirrus bulb, 

 where it turns abruptly towards the margin to open immediately in 

 front of the cirrus. Immediately in front of the inner end of the cirrus 

 bulb it enlarges suddenly into a vaginal sinus. This vaginal enlarge- 

 ment, in one section, was .2 mm in length and .04 mm wide at widest 

 part. The beginning of the narrow part appears to be lined with minute 

 bristles. A few loose spines of the cirrus were observed in the vaginal 

 sinus. These may have been carried over from the base of the cirrus, 

 which lies near by, by the knife, or they may have become detached 

 from a cirrus during copulation before the specimen was killed. 



In the free proglottides with ripe ova, there is a large oval aperture 

 on one of the lateral faces for the escape of ova. One of these oval 

 apertures measured A and .3 mlu in its two diameters. In these ripe 

 proglottides the ova fill up almost the entire interior. The proglottides 

 are in fact converted into mere sacs containing ova. In the alcoholic 

 specimens the ova are small, granular, with a thin, irregular, and col- 

 lapsed investing membrane. The diameter of the granular part is .02 m,n . 

 The ovaries are elongated oval organs occupying the posterior third of 

 the segment, extending from the posterior end of the segment almost to 

 the cirrus bulb. 



The costate appearance of some of the prolongations of the edges of 

 the bothria, which was alluded to and figured in the original account 

 of this species, was not properly understood when the original descrip- 

 tion was written. It is to be accounted for, I think, in this way : When 

 the border of a bothrium is prolonged, the prolongation will, of course, 

 be bordered by the marginal row of loculi. As a prolongation becomes 

 narrower, it is at the expense of that part which lies within the marginal 

 loculi. In very narrow prolongations the row of loculi on opposite sides 

 of the prolongation become approximated on either side of a line which 

 is made up of the inner edges of the two rows of loculi. Such a iiap 

 when flattened out looks something like a linear pinnate leaf with a 

 prominent midrib. 



In this lot of specimens, as in the lot which furnished the basis of my 

 former description, there are two varieties. In one the anterior and 

 median segments are uniformly broader than long, becoming squarish 

 toward the posterior end, the margins of the strobile crenulate. In the 

 other the segments soon become longer than broad, slender with par- 

 allel margins, the strobile filiform with entire margins. These two 

 forms are figured in my former paper. They probably arise from dif- 

 ferent states of contraction, but it is somewhat singular that each small 

 lot should furnish examples of these two distinct forms. 



