ACANTHOCHEILONEMA PERSTANS 



643 



Type, — AcanthocheiloneMa dracunculoides Cobbold, 1870. 

 Other species are A. perstans Manson, 1891 (A. recondita Grassi, 

 1890; and A. grassii Noe, I907.) 



Acanthocheilonema perstans Manson, 1891. 



Synonyms. — Filaria perstans Manson, 1891 ; F. sanguinis hominis 

 minor Manson, 1891; F. sanguinis hominis perstans Manson, 1891; 

 F. ozzardi (variety truncated) Manson, 1897. 



History.— The microfilaria was first found by Manson in the 

 blood of negroes from the Congo. Daniels found the adults in 

 British Guiana. The geographical distribution known at present 

 is Tropical Africa and British Guiana. 



Morphology. — 'The adults are found, as a rule, free in the con- 

 nective tissue at the base of the mesentery, around the pancreas, 

 behind the pericardium, and behind the abdominal aorta and the 

 suprarenal capsules. The body is cylindrical, uniform, except 

 towards both ends, when it tapers a little. 



Fig. 274. — Embryo of Acanthocheilonema perstans Manson. 



The male, rarely met with, is 45 millimetres in length by o-6 milli- 

 metre broad, with a greatly curved tail, which ends in a bifid pro- 

 longation of the cuticle. Low describes two unequal spicules and 

 four pairs of pre-anal and one of post-anal papillse, all of which are 

 very small. According to Leiper there are two pairs of post-anals. 



The female is 70 to 80 millimetres in length and o-i2 millimetre 

 in breadth, with a rounded head and a long neck. The incurved 

 tail ends in two triangular cuticular lobes. The mouth is simple 

 and small, and the alimentary canal shows no differentiation i^to 

 oesophagus or intestine. The anus opens upon a papilla 0-145 milli- 

 metre in front of the tip of the tail. The uterus is double, and, 

 when full of eggs and embryos in various stages of development, 

 nearly fills the body. The vulva is o-6 millimetre behind the anterior 

 extremity. 



Life-History. — The egg undergoes its development in the uterus, 

 and the microfilaria escapes from its egg membrane and appears 

 in the peripheral circulation without a sheath, and, consequently, 

 can move about on a slide. It measures 190 to 210 [Mm length and 

 4'5 to 5 in breadth. It is covered with a finely striated cuticle, 

 and has a retractile spine, situated (apparently) upon a papilla at 

 the anterior end of the body. The posterior two-thirds of the body 

 tapers to the tip of the tail, which is abruptly rounded off. 



