C. L. Boulenger 
241 
in England 13 species, distributed among 10 genera, that is to say 
nearly half of the known species. 
My material was obtained from various sources ; thanks to the 
courtesy of Mr Brailsford I was able to examine a number of sheep 
and lambs from the Birmingham slaughter houses, other animals were 
procured from farms in the neighbourhood of this city, whilst a number 
of interesting observations were made at Wye in Kent during a short 
visit to the South Eastern Agricultural College in August 1913. 
I should like to acknowledge here my great indebtedness to Mr H. E. 
Hornby of that institution for placing a quantity of his material at 
my disposal and for his generosity in giving me the benefit of his large 
experience of the parasitic diseases of sheep. 
In this paper no attempt has been made to give complete descrip¬ 
tions of the various species observed and the commoner and better 
known forms are merely mentioned by name; in the case of some of 
the rarer and less easily identified forms short descriptions are given 
together with some measurements and figures, partly to supplement 
previous accounts, but chiefly in order that others may judge as to 
the accuracy of my determinations. Among such forms special atten¬ 
tion may be called to the following : 
Ostertagia trifurcata Ransom, previously known from the United 
States only^ ; Cooperia oncophora Railliet, known from cattle in Europe 
but not before recorded from the sheep in this country, and the three 
species of Trichostrongylus of which little seems known in England. 
Glycerine mounts were found the most satisfactory for the micro¬ 
scopical examination of the specimens, the worms being killed in hot 
70 per cent, alcohol and glycerine according to the well-known method 
first suggested by Looss. For the elucidation of the finer structure of 
the spicules it was sometimes found desirable to use a mounting 
medium of higher refractive index than glycerine. A convenient 
medium is one sometimes used by entomologists for the examination 
of the more delicate chitinous structures in insects, this consists of 
10 parts of a saturated solution of gum arabic in cold water, 1 part 
of glycerine, 1 part of chloral hydrate, 1 part of glacial acetic acid 
and 1 part of 95 per cent, alcohol. Specimens may be transferred 
directly from water or alcohol into this medium which has the addi¬ 
tional advantage of solidifying rapidly. 
^ For the first record of Ostarlagia trifurcata in England, priority must be given to 
Mr T. Storrar Cave, whose note on this species, published in the present number of this 
Journal (p. 201), was received for publication before Dr Boulenger’s paper.—E d. 
