432 DR. F. E. BEDDARD ON 



devoid of hooks. The one Avhich showed them only possessed 

 a few, which needed a high-power lens and good illumination to 

 show them up. It seems to me that they may easily be shed. 

 I am quite unable to make any statement as to the shape of 

 these hooks. They appeared to be little more than acicular in 

 form, like the hooks of the suckers in some Davainea. The 

 feebleness of the rostellar hooks seems to me to be related to the 

 little marked character of the rostellum in this and other forms. 

 I may remark that there is no reason to believe that the present 

 species has any hooks upon the suckers *. I shall return later to 

 the questions of systematic arrangement which depend upon the 

 presence of hooks in connection with the genera ZscIiohJceella and 

 Inermica'psifer and some others. 



In spite of the fact that Chapman described the genital pores 

 of his species as alternating irregularly, the genus Chapmanicif 

 has been defined by some subsequent writers as unilateral, at any 

 rate in the particular species Chapmania tauricollis f. Chapman 

 himself remarked that five pores might follow consecutively upon 

 the same side of the body. I have seen ten segments in series 

 with the genital pores all upon the same side. It is therefore 

 obvious where the error may have crept in. The genital pores 

 lie at about the middle of the lateral border. 



I shall now deal with a few points in the internal structure of 

 this Cestode. 



The cirrus-sac does not seem to me to have been fully described 

 by Fuhrmann. The cloaca genitalis, as he has pointed out, is 

 deep and expands within the cortex in a funnel-shaped way. 

 Into the middle of this funnel opens the cirrus-sac, and through 

 it projects often the protruded cirrus. The cirrus-sac appears to 

 consist of two distinct regions, or it may be, as I shall point out 

 later, that the cloaca genitalis consists of two distinct regions. In 

 any case a bottle-shaped sac opens into what is unquestionably 

 the cloaca genitalis, the neck of which " bottle " is much shorter 

 than the rest. This relatively narrow tube has muscular walls 

 quite continuous with those of the rest of the cirrus-sac, and in 

 it lies the cirrus, which nearly fills up its lumen in cirrus-sacs, 

 which are in an average state of protrusion of the cirrus. The 

 rest of the cirrus-sac extends into the bodj^of the worm some way 

 inwards of the lateral water- vascular tube and ends in a retractor 

 muscle, as has been described by Fuhrmann, The flask part of 

 the cirrus-sac is divided from its nari-ow neck by a sphincter- 

 muscle, Avhich forms a collar within the lumen of the sac, and to 

 the inside of this a fan-shaped bunch of muscular fibi-es, provided 

 with nuclei at their internal ends, further blocks the lumen and 



* Fuhrmann, however (Rev. Suisse Zool. iv. 1896, p. Ill), not only refers to hooks 

 upon the rostellum, but speaks of having seen the evidence of hooks upon one 

 sucker. The definitions of the genus Chapmania given b}' Fuhrmann and Ransom 

 do not use hooks upon the suckers as a character of that genus. 



1 1, e., Ransom, ]?roc. U.S. Nat. Mus. vol. xl. 1911, p. 637. Also used as'a character 

 oi"Teenia arqentina" (believed to be sj'nonymous bj- Zschokke, Centralb. Bakt. u. 

 Paras, iii. 1888, p. 1). 



