800 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [82] 



In the summer of 1886 and 1887 I had several opportunities of exam- 

 ining this shark. In each iustance I found this entozoon in abundance, 

 aud usually no others. I take the followiug data from my memoranda 

 made at the time of collecting : 



August 2, 1886. — Eighty-one specimens of C. laciniatum, adult and 

 young, obtained from the spiral valve of a single sand shark (0. litto- 

 rails). The chyle was swarming with mature proglottides. Oue indi- 

 vidual of this lot differed from all other specimens of this parasite that 

 I have yet seen in having a moderately elongated neck. In the normal 

 form the neck is short and corresponds to one of the anterior segments. 

 A description of this unusual form is given below. No other entozoon 

 found, except a few cysts (Xenosites Yan Beueden) in the muscular 

 coats of the stomach and intestine. 



July 13, 1887. — Seventy-five specimens of same parasite, young and 

 adult ; same host ; no other entozoon found. 



July 22, 1887. —Fifty- three specimens of same, maximum length 

 160 mm j same host ; no other entozoon. 



August 12, 1887. — Ninety-two specimens of same, mainly immature, 

 maximum length 40 mm ; same host ; also five small Rhynchobothria and 

 one Nematod. 



August 13, 1887, — Forty-four specimens, mainly adult, maximum 

 length, 125 mm ; same host ; also five JSTematods, four large and one small, 

 with their heads embedded in the mucous membrane of the stomach, 

 near the pyloric constriction. In this lot there was an abnormal form 

 which measured only 18 mm in length, but which had mature segments. 

 This form is more fully described below. 



Variety longicolle. — The abnormal form found in the lot of August 2, 

 1886, deserves something more than a passing notice. It is the only 

 one of all that I have yet found that has a distinctly elongated neck. 

 In other cases, with this single exception, the length of the neck, ihat 

 is, the distance from the bases of the pedicels of the bothria to the first 

 segment, is about equal to the length of the first segment. In other 

 words, the segments begin immediately behind the head. 



When first measured, which was after it had lain in sea- water about 

 eighteen hours, the length of this specimen was 14.7 mm , the length of 

 the neck 2 mm . The first segment at this time was enlarged and inflated. 

 This latter feature disappeared in a few hours and the neck became 

 relatively longer and thinner. After having been in sea-water for 

 twenty-four hours, the length of the specimen was 21 mm , its neck 5 mm . 

 There were eighteen segments in the strobile, all of which seemed 

 to be adult and equally developed, while the last two were mature and 

 contained ova. In this respect it was in sharp contrast with the other 

 individuals of this and other lots, which had mature segments. These, 

 as a rule, measured from 100 to 200 mm and over, in length, the anterior 

 and median segments being immature. On the other hand, the dimen- 

 sions aud general appearance ot the head and bothria are in no essential 



