DESCRIPTION OF FILARIA MAVIS. 



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is 0*26 mm., at 0'5 mm. 0"22 mm., rapidly dwindling to 0*06 mm. 

 at the anus. 



The vulva opens at 0*4 mm. from the mouth. The vagina is 

 exceedingly short, only 0*05 mm., and divides almost at once 

 into two uteri that pass backwards for about 05 mm. Each tube 

 then twists upon itself and proceeds with increasing diameter to 

 attain a thickness of 0*1 mm. at about 2 mm. behind the mouth. 

 The two uteri pass backwards side by side and in close contact 

 for a distance of 4 mm. Thereafter they diverge slightly, the 

 chyle intestine occupying the intervening space, but continue 

 their course to within 3'5 mm. of the posterior end of the body, 

 when they abruptly terminate, within half a millimetre of each 

 other, in fine ovarian tubules that occupy the succeeding milli- 

 metre with their numerous coils. The remaining two and a half 

 millimetres of the body is traversed by the chyle intestine alone. 



The alimentary canal closely resembles that of the male, the 

 oesophagus is crossed by the nerve-ring at 0*13 mm., and termi- 

 nates in the chyle intestine at 0'75 mm. from the mouth. The 

 anus opens at 0'1 mm. from the posterior extremity. 



Nomenclature. 



The adult filaria that have been found hitherto in members 

 of the genus Turdus and in allied forms have been provisionally 

 identified as Filaria abbreviata, Rud., apparently without in- 

 vestigation of their minute structure. 



The specimens described in this paper cannot belong to 

 this species, for there are characteristically present in Filaria 

 abbreviata deciduous spines on the cuticle, an infundibuliform 

 pharynx armed with teeth, and the spicules are dissimilar both 

 in size and design. 



Filaria turdi, v. Linstow, is apparently the same, or a closely 

 allied species of Spiroptera as occurred beneath the mucosa of 

 the stomach in one of our birds. Filaria turdi olivascentis, Molin, 

 and Filaria turdi atrogularis, v. Linstow, are unacceptable names 

 according to modern rules of nomenclature, although the latter 

 species appears from its too brief description to approach some- 

 what closely to the parasite now described. Under these circum- 

 stances it is obvious that our Filaria of Tardus musicus must be 

 recorded as a nomenclaturally new species, Filaiia maris, mihi. 



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