SOME MAMMALIAN TAPEWORMS. 639 



contrary to what is more usual, in the colon and not attached 

 to the walls of that gut. It may be, therefoi'e, that the parasites 

 had been loosened from their attachment in the small intestine 

 and had drifted into the colon, of which portion of the ali- 

 mentaiy ti"act they are therefore not really iidaabitants. However, 

 both specimens were quite alive and exhibited writhing move- 

 ments, and it is possible therefore that they are really parasitic in 

 the colon. They were of about the same size, and shrunk con- 

 siderably on preservation in alcohol. One of the two specimens, 

 which I have preseived entire and regard as the type of the 

 species, measures in the alcoholic condition 150 mm. It is re- 

 markable foi- the extreme shortness and great width of the 

 segments, and agiees in this particular with species of the genus 

 Bertiella, of wliich other anatomical characteis pi'ove it to be 

 a member. 



The anterior extremit}'- (as is shown in text-figure 151) is ver}-^ 

 minute, and the body gradually Avidens up to a diameter of some 

 10 mm. Its general appearance is thus not precisely, although it 

 is genei'ally, like that of other species of this genus. Accompany- 

 ing the increase in width of the proglottides there is also an 

 increase in thickness, and the posterior end of the body is about 

 2-3 mm. thick. In addition to the two specimens of the worm 

 thei'e was a detached piece, possibly of one of these, of about an 

 inch in length. It appeai-s to me that, as in Bothriocephahis, for 

 example, the proglottides are not shed singly but in groups. The 

 head of the worm is black in parts, the arrangement of the pigment 

 being peculiar, as I shall describe shortly. This black-headed 

 condition suggested to me that we might be dealing here with 

 examples of P. van Beneden's Tcenia mela7iocephala *, a parasite 

 fi'om another species of African Monkey. The other chaiacters 

 given by van Beneden are in perfect hai-mony with this view of 

 the identity of the species, but, as Blanchard f has pointed out, 

 the characters given are really not enough to determine the genus 

 to which T(enia melanocephala belongs, let alone the species. 



Nor does ni}^ discovery here recorded of a black-headed Tape- 

 worm found in an African Monkey, and clearly referable to the 

 genus Bertiella, in any way settle the point at issue. For, in the 

 first place. I have found in a species of Davainea (or, at any rate, 

 an allied genus) the same distribution of the pigment in the head 

 that will shortly be described in the species now under consider- 

 ation ; so that the mere presence of pigment in the head is clearly 

 no criterion of the identity of the worm. In the second place, 

 another species of Bertiella, viz. B. mxicfi^onata, also from a monkey, 

 has been described X iii which the head is likewise pigmented. It 

 will be shown later that my species is not Bertiella mucronata. 

 Moreover, there is no reason, owing to the defective description 

 of van Beneden, for the identification of B. melanocephala with 

 B. mucronata. Thus it is necessaiy, as I think, to ^\q ? new name 



* M^m. sur les Vers intestinaux, Paris, 1859, p. 162. 



t Mem. Soc. Zool. France, 1891, p. 186. 



j Meyner, " Zwei neue Tsenien aus AfFen," Zeitschr. f. Naturw. 1895, p. 1. 



45* 



