556 NEMATODE PARASri'ES OF TlIK DOMESTIC PIGEON, 



slit U.04U iiim. wide. The boily is U.U44 uuu. iu diameter id the anus. Be- 

 hind it the slender tail (Text-fig. 3) ends bluntly; the fine terminal spine which 

 it bears, is about 0.015 mm. long, and penetrates the cuticle to connect with the 

 internal protoplasm. It appears to te hollow, and of a glandular nature. 



Each lobe of the male bursa (Text-figs. 4, 5)' measures about 0.143 mm. in 

 width, and 0.130 to 0.170 mm. in depth. The tips of the two ventral rays are 

 only 0.006 mm. apart. Of the lateral rays, the externo-lateral is the longest, 

 and is curved \entrally, its tip being some distance from the margin of the 

 bursa, and 0.034 mm. from that of the latero-ventral . The distance between 

 the posterolateral and externo-dorsal is a little less, 0.028 mm. The distances 

 between the tips of the lateral rays are greater, 0.04fl mm. between postero- and 

 medio-lateral, and twice as much between medio- and externo-lateral. The pre- 

 bursal papillae are 0.013 mm. long, and are situated laterally, 0.052 mm. in 

 front of the base of the bursa. The two equal spicules (Text-flg. 6) measure 

 0.148 mm. long, and taper distally to end in three slender pointed branches, 

 which are surrounded by the chitinous supporting piece, 0.041 mm. long. 



Stevenson states that this worm, when present in large numbers, causes a 

 debilitating diarrhoea, and general disorder of the nutritive functions of the host 

 bird This he thinks to be due both to a loss of blood, and to the piercing of 

 the mucosa, leaving open channels for fatal infection with bacteria. Shipley 

 (1909") includes the species in his list (p. 335) of those harmful to birds, and 

 Ncumaiin-l\facqneen (1905). and Neveu-Jjcmaire (1912). referring evidently to 

 Stevenson's statement, both record it as producing grave disorders, bacterial in- 

 fection, catarrh, and profuse diarrhoea. 



But in this case there was no evidence that the worm, though present in fairly 

 large numbers, caused any harmful effect. The walls of the intestine were not 

 in nn inflamed catarrhal condition, and. as already stated, ajipeared to bo perfectly 

 healthy . 



Family TRICHINELLTDAE Stiles and Cvaiio, 1910. 



Subfamily TRICHURINAE Ransom. 1911. 



Genus Capillakia Zeder, 1800 . 



Generic diag)!osis (from Hall 1916).— Body very slender, capillary: anterior, 

 oesophageal portion of body shorter than, or rarely equal to the posterior portion 

 of body. Bacillary band dorsal, ventral, or lateral, or absent. Oesophagus long 

 and slender, gradually increasing in size posteriorly. Spicule long and slender, sur- 

 rounded by a sheath which may present a smooth outer surface when evaginated, 

 or a surface armed with spines. Tail of male may or may not be provided with 

 membranous wings, and a membranous bursa-like structure, these being usually in- 

 conspicuous when present. \'ulva located near the base of the oesophagus. Eggs 

 lemon shaped, with the usual opercular plugs. 



Type species, Capillaria tumida Zecler, 1803 (= Tritiioicp/ia/iis ana/is Sclirank. 

 1790 = Trichosoina hrevicolle Kudolplii, 1819). 



This genus, established by Zedcr to include forms characterised by a filiform 

 l)ody, with a very slender anterior part merging almost insciisildy into a I'ather 

 tliicker posterior jtart, was renamed Tricluisowa b.y Rudolidii in 1819. Tt is under 

 this name that most of its species have since been described, the original name 

 being re-established by Stiles and Hassall only in 1905, when they published their 

 "Determination of Generic Types, and a List of Roundworm Genera." 



