426 WILLIAM NICOLL. 
Sub-family Bracnyciapimn® Odh., 1904. 
Genus Brachycladium Lss., 1899. 
Brachycladium oblongum (Braun). Pl. 9, figs. 6—9. 
? = Campula oblonga Cobbold. 
1900. Campula oblonga Cobb. Braun, ‘Centralbl. f. 
Bakter.,’ xxviii; ‘ Abtheil.,’ 1, pp. 249-255, 3 figs. 
1902. Brachycladium oblongum (Brn.), Looss, ‘Zool. 
Jahrb. Abth. Syst.,’ xvi, pp. 707-717 and 775-778. 
1904. Brachycladium oblongum Odhner, ‘ Die Trema- 
toden des arktischen Gebietes, Fauna Arctica,’ iv, p. 347. 
This species has been the cause of much systematic dis- 
cussion, and its ultimate fate may be regarded as a critical 
test of the priority law as applied to zoological nomenclature. 
The root of the trouble lies in the fact that Cobbold’s type 
specimens of Campula oblonga have been lost or destroyed, 
and that his description’ of the species is inadequate to 
differentiate it from allied and more recently discovered 
species. I have made an exhaustive but fruitless search for 
Cobbold’s specimens, and it may certainly be considered that 
they no longer exist, unless, perchance, in some _ private 
collection. What remains to us, therefore, of Cobbold’s 
species is merely his scanty description, which, as Looss 
justly remarks, is of no value whatsoever for diagnostic 
purposes. Braun’s identification, as Campula oblonga 
Cobb., of a species which he found in the same situation in 
the same host as Cobbold found his specimens, is regarded 
by Looss as inadmissible, and his opinion is seconded by 
Odhner. Braun defended his diagnosis on the ground of the 
similarity of habitat and the manifest resemblance between 
his specimens and Cobbold’s description and figure so far as 
they went, but Looss pointed out that Brachycladium 
palliatum Lss., Br. rochebruni Poir., and Br. delphini 
Poir. resemble Cobbold’s Campula oblonga just as closely 
as do Braun’s specimens, and so might just as readily be 
1 «Trans. Linn. Soc. Lond.,’ xxii (1858), p. 168, Pl. XX XIII, figs. 84, 85. 
