SOME MAMMALIAN TAPEWORMS. 651 



obvious in young proglottides, which are so slender that the 

 disposition of these structures can be seen in a single section. 



A final point of systematic impoitance concerns the horn-like 

 processes of the innermost egg-shell, which are figured by Meyner 

 and stated by him to be always veiy obvious. I have been abso- 

 lutely unable to detect these structures, e\'en when using an oil 

 immersion-lens (yV in. Leitz). We must, therefore, agree that 

 this group of species of Bertiella is to be characterised, as the 

 two remaining groups into which Zschokke divides the genus, by 

 '' birnfbrmiger Apparat nicht constant." I am unable to compare 

 the species which I describe liere as Bertiella cercopitheci with two 

 species described by Gottheil * from Macacus cynomolgus and from 

 that species and Cebus capucimis, since they ai'e not sufficiently 

 diagnosed, and Stiles is of opinion that they are only doubtfully to 

 be referred to the genus Bertiella. Indeed, the position of the 

 genital pores is not refei^red to. 



Another Monkey parasite with which my Tapeworm might be 

 compared is v. Linstow's Bertiella polyorchis'j h-om I/acactis cyno- 

 molgus. This is interesting, fi'om the point of view of the egg- 

 shells, and confirms what I have said above concerning the absence 

 of the horn-like processes in B. cercopitheci ; for it is hardly likely 

 that so experienced a, helminthologist as Dr. von Linstow would 

 have overlooked these structures weie they present, and his figure 

 of the eg^g of B. polyorchis does not show them. Furthermore, 

 the suckers look forward and a dilation of the spenii-duct within 

 the cirrus sac is figured. The species, however, diff"ers, as I 

 believe, from Bertiella cercopitheci by its less complicated vagina, 

 by the much greater number of testes which fill the middle of the 

 proglottid, and by the absence of any black pigmentation in the 

 head. At any rate, the latter point is not referred to. 



Thysanosoma gambianum, sp. n. 



I obtained from an example of the Gambian Pouched Rat, 

 Cricetomys gambiamcs, which died in June 1909, a considerable 

 number of Tapeworms which I regard as being of a new species 

 and belonging most probably to the family Anoplocephalidse. The 

 Rodent had been one year and ten months in the Society's 

 Gardens before its death, and it is, therefore, quite credible that 

 it was infected with these Cestodes when it arrived in London. 

 The material, as well as being abundant, was well preserved, and I 

 am therefore able to give a fairly comprehensive account of the 

 anatomy of the species, which presents certain new combinations 

 of characters. 



The external characters alone appear to place this worm in 

 either the genus Anoplocephala or Zschokkeella. There are no 

 other genera in which the scolex is unanned, the genital pores 

 are unilateral and the neck is absent, and the segments until the 



* Jouni. Comp. Med. & Surgeiy, 1887, vol. vii. The species are not named and 

 are referred to Tcenia. 

 t Arch. f. Naturg. Ixxi. 1905, p. 270. 



