286 BULLETIN OF THE UNITED STATES FISH COMMISSION 



Octobothrium denticulatum Olason. 

 [ Plate 33, figs. 6-10, U. S. N. M. Xo. 5(.ix. Hi drag till Skandinaviens Helmiiitlifauna (1876), page 10, Plate I, figs. 13-17.] 



A single specimen collected July 14, by Prof. H. M. Kelly, from tlic gills of the pollock (Pollachiiis 

 rirena) agrees closely with Olsson's species, whose synopsis I translate: 



"Body depressed, ovate-oblong, tail large, assuming half the length of the animal, canaliculate, 

 each plectauum bearing four pedicels, the pedicels short, cylindrical, their anterior valves extrinsically 

 denticulate. Testes in the postero-median part of the body near the tail. Ova with a filament at 

 eachlfxtremity. Length 7 mm., breadth 2 rum." 



The following notes were made on the alcoholic specimen : Head bluntly triangular; body lance- 

 olate, slightly constricted behind the head ; bothria a little longer than broad, approximating in length 

 to subglobular pharynx. Anterior end for about 0.8 mm. and pedicels white, with tinge of yellow, 

 also white spot in middle and white along mid line near anterior end; remainder of body dark brown. 

 This for the dorsal side; ventral side same, but paler on the brown parts, and the mid line is white 

 from the anterior end to about the level of the second pair of pedicels. Each pedicel appears to 

 expand into a two-valved disc at the extremity, the valves being supported by a chitinous framework. 

 There is a cluster of denticulate papilla' on the anterior outer fourth of each disc, on what, when it 

 is expanded, is its dorsal surface. Two dark-brown ova lay on the median line about 1 mm. back of 

 the pharynx. These were oblong and had a slender filament at each end. The character of the 

 filaments could not be made out exactly without mutilating the specimen. 



Dimensions of alcoholic specimen in millimeters: Length 8; breadth, anterior 0.39, in front of 

 pedicels 2, including pedicels 3.5; diameter of single disc 0.65; breadth of one of anterior bothria 0.14, 

 length of same 0.16; breadth of pharynx 0.16, length of same 0.17; length of ovum not including 

 filaments 0.19, breadth of same 0.07; length of single filament 0.14. 



The cirrus, which is armed with a circle of fourteen bifurcate hooks, opens on the mid-ventral 

 line 0.17 mm. back of the pharynx. The length of these hooks is about 0.02 mm. The arrangement 

 of the reproductive organs could not be made out. The vitellaria fill up the greater part of the body, 

 extending from the extreme posterior end, even going a short distance into the bases of the posterior 

 pedicels, to within less than 1 mm. of the anterior end. The testis and ovary could be seen lying a 

 little in front of the anterior pedicels, but they were so much hidden by the voluminous vitellaria that 

 their outlines could not be made out. 







Epibdella bumpusii sp. nov. 



[Plate 34, figs. 11-15, IT. S. N. M. No. 6509.] 



My attention was first called to this beautiful and interesting form by Dr. Hermon C. Bumpus. 

 Several specimens were obtained on August 18 from the exterior of the stingray (Dazyatis centrum). 



Body flat and leaf-like, smooth, ovate, slightly constricted behind the anterior suckers, bluish- 

 white and transparent. Anterior suckers crossed by about 22 ribs. Posterior sucker attached by 

 pedicel at posterior margin of body, elliptical, the length slightly exceeding the breadth, armed with 

 four hooks; the two anterior hooks straightish on the inner and convex on the outer margins, as seen 

 in dorso-veutral view; the two posterior hooks longer, more slender and arcuate, being curved 

 toward the lateral margins. Pharynx subglobular. Testes two, about the middle of the body, on 

 opposite sides of the median line, subspherical. Ovary a short distance in front of testes, triangular 

 in outline. Vitelline reservoir immediately in front of ovary and a little toward the left. Repro- 

 ductive apertures on left side of neck at marginal notch. Cirrus, uterus, and vagina open near 

 together, the former being the most anterior and the others following in the order named. Larger 

 part of the body occupied by the vitelliue glands. Ova tetrahedral, with long, slender filament, 

 ejected from uterus as fast as made. 



Dimensions of living specimen, in millimeters : Length 12.5, breadth 8.35, breadth of posterior 

 sucker 4.4, length of anterior sucker 1.25, breadth of same 0.31, breadth of pharynx 0.71. Other 

 specimens were somewhat smaller. In a specimen mounted in balsam the length of the ventral 

 sucker is 3.2, the breadth 2.4 ; the length of the longer hooks is 0.85, of the shorter 0.6. The length 

 of the body of this specimen, exclusive of the ventral sucker, is 8, breadth 4.5. 



Although somewhat aside from the main purpose of this paper, I append a few observations on 

 the process of ovulation in this species, first as seen in operation in the living worm, and second as 

 confirmed by a study of serial sections. 



