84 CH. WARDELL SïILES AND ALBERT HASSALL 



Dujardin mentions in 1845 as « var. a » of Distoma migrans, and 

 D. migrans is simply B. advena renamed. B. advena must, therefore, 

 stand as type of the genus Brachylaima, an unfortunate fact which 

 may resuit in considérable temporary confusion in nomenclature. 



In 1845 Dujardin reduced Brachylaima to subgeneric rank (as 

 Brachylaimus) and added a number of species, which he divided 

 into five sections. In 1847 E. Blanchard restored it to generic rank, 

 changing the spelling to Brachylsemus, and taking Fasciola cylin- 

 dracea and Distoma variegatumas types, a désignation which cannot 

 possibly be accepted as neither of the forms were originally men- 

 tioned by Dujardin (1843) when the genus was proposed. 



Dujardin (1843) says that the cirrus is absent in B. advena, a 

 statement which he queries in 1845 ; the maie génital opening is 

 described as halfway between the acetabulum and posterior extremity, 

 while the vuha is said to be situated anterior of the acetabulum. 



We hâve searched in vain for later descriptions or figures of 

 B. advena. It is clear that the fate of the genus Brachylaima dépends 

 upon the correctness of the anatomical description given by Dujar- 

 din. Should this species be re-examined, and Dujardin's statements 

 be confirmed, there will probably be no doubt regardingthe status 

 of the genus. Should his interprétation of the anatomy prove to be 

 incorrect, the genus must be judged upon the characters found. 



From the above it is évident that the use of Brachylaima or Bra- 

 chylaimus in the sensé now adopted by many helminthologists is 

 unjustified, since the chief character proposed for the genus by 

 Dujardin (Bifurcation de l'intestin située immédiatement après le 

 bulbe œsophagien. Sans tube ou appendice protractile en arrière), 

 and adopted by many authors, must be subservient to the complex 

 of anatomical characters, among which the position of the génital 

 openings is one of the most important. 



This case is an excellent illustration of the necessity of designating 

 a type as a standard of référence for a genus. 



Brachylaimus see Brachylaima. 



Bunodera Railliet, 1896. — Type, Distoma nodulosum (Zeder, 

 1800) =^ Fasciola luciopercae Miiller, 1776. 



1845, Distoma (Crossodera) Dujardin [nec (1) Crossodera Gould, 

 1837], Histoire nat. des helminthes, pp. 382, 389, 434. 



(1) Crossodera Gould, 1837, Bird. 



