830 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [112] 

 Following is a list of the captures of this worm : 



Date of capture. 



No. of dog-fish examined. 



No. of specimens of R. tumi- 

 dulum obtained. 



1886. 

 July 23 



Three 



Twelve. 



24 



If our 



Five. 



31 



One 



Six 



Two. 



1887. 

 19 



Eighteen. 



Eight. 



Two. 



21 



Ten 



23 



One 



Aug. 4 



10 



Three 



One. 



Three 



One. 



11 



Two 



Fifteen. 









Accurate measurements of the living worm are very difficult to ob- 

 tain on acqount of the extreme variability of form due to the excessive 

 contractility. The longest specimens measure from 10 to 12 mm and con- 

 sist of from twelve to fourteen distinct segments. In one specimen, 

 which measured 10 mm in length and had twelve segments, the last seg- 

 ment varied in length from 1.5 to 4 mm , with different degrees of con- 

 traction. The head and neck in this specimen were much contracted, 

 and measured l mm in length. Of the twelve segments, the first four 

 or five were very short and crowded together, the next squarish, the 

 following ones longer than broad, the last three capable of considerable 

 elongation. The posterior end of the last segment was deeply and 

 abruptly emarginate. The bothria appeared to be marginal. 



The following measurements are of living specimens: 



Dimensions. 



Length 



Length of bothrium 



Breadth of bothrium 



Breadth of head 



Length of head and neck 



Diameter of neck 



Length of last segment . . 

 Breadth of last segment . 



No. 1. No. 2. No. 3 



mm 

 5.20 



0.26 



0.54 

 0.80 



1.46 

 0.44 



mm 

 5.40 



0.30 



0.30 



1.00 

 0.44 

 1.30 

 0.46 



mm 

 11.60 



3.20 

 0.80 



For No. 3 of the above table the following additional measurements 

 are given: Length of last segment but one, 2.80 ram ; breadth, 0.72 mm ; 

 distance from base of contractile bulbs to first distinct segment, 0.20 mm ; 

 length of first distinct segment, 0.08 mm ; breadth, 0.36 ,nm ; number of seg- 

 ments, 14 j length of crimson spot in the contractile neck, 0.44 mm ; 

 length of contractile bulbs, 0.40 mm . The crimson spot in front of the 

 contractile bulbs is due to the coloration of grauules in the parenchyma 

 of the neck. It is quickly dissolved by alcohol. 



