188 TAPEWORMS OF HAKES AXD RABBITS STILES. 



I can add a few points of importance to Riehm's diagnosis and lay 

 greater stress upon other points which 1 think should be brought out 

 more emphatically. 



The anlagen of the female glands and genital canals appear in the 

 earliest segments, while the testicles begin about 7 mm. back of the 

 head. Male organs: The testicles are confined entirely to that portion 

 of the segment which lies distally of the uterus, and they extend on 

 both sides laterally of the ovaries to the longitudinal canals ; this latter 

 character is one of considerable importance when we compare the Ameri- 

 can and the European forms. Riehm has already directed attention to 

 the loughoselike cirrus pouch and vagina, but I venture to call particu- 

 lar notice to their size and form. 



Female organs: The excessive development which the female glands 

 may attain is worthy of note: Riehin's statement that each ovary 

 was divided into two halves I was unable to confirm. A peculiar 

 feature of the female glands is that they develop suddenly and atrophy 

 suddenly. In Riehm's cotype, for instance, the tubes of the ovary be- 

 come visible 8 mm. from the anterior end (head lost) ; they then develop 

 rapidly to a maximum and suddenly disappear, so that 22 mm. from the 

 point where the ovarian tubes appear (or about 30 mm. from the anterior 

 extremity) the ovary can no longer be seen; the testicles persist very 

 much longer. The first trace of the uterus is seen about 12 mm. from the 

 anterior end of specimen (about 14 mm. from anterior end of individual, if 

 we allow 2 mm. for the lost head and first segments); the uterus passes 

 on the ventral side of the ovary, and in all segments which I have exam- 

 ined there is a single uterine anlage extending across the segment. 



The genital canals and uterus run dorsally of the nerve and ventral 

 canal as Eiehm figures them, and on transverse sections the cirrus is 

 shown to lie dorsally of the vagina on both sides of the segment. The 

 nerve is very close to the lateral margin. 



Kiehm gives no measurements for the ova; Blanchard (1891, p. 460) 

 states that the ova measure to 90 /; by 75 /v, and that the bulb of 

 the pyriform body measures 25 to 30 IJL in diameter. The measurements 

 in Riehm's specimen are somewhat smaller, the ova varying from 72 to 

 84 ^ the bulb of the pyriform body 14 to 16 y. My own specimens 

 agree with Riehm's, but many of the ova do not exceed 56 ^ in 

 diameter. 



The following is proposed as a revised specific diagnosis: 



Diagnosis. Cittotcenia pectinata (Goeze, 1782, partim, Riehm, 1881), 

 Stiles & Hassall, 1896. Strobila may attain 400 mm. in length and 8 

 mm. in breadth, anterior portion usually lanceolate. Head small, about 

 0.25 mm. or less in diameter, and about 0.125 mm. thick; rostelliui and 

 hooks not observed; suckers small. Neck very short, segmentation 

 beginning almost immediately back of the head; the proglottids rapidly 

 become distinct and are always much broader than long, the length being 

 about one-seventh of the breadth; gravid posterior segments measure 



