188 DE. T. S. COBBOLD OK A NEW ENTOZOON. 



dissolving fibrine, it is likely that its absorption by endosmose when 

 brought into contact with the worms would destroy them. It is not 

 probable that any difference of action would result by employing the 

 drug for the destruction ahke of Strongyles, Ascarides, Oxyurides, or even 

 Filarias. I would strongly advise the Ostrich-farmers to give Pawpaw a 

 fair trial. To some it will natiu-ally occur to recommend santonine ; but 

 seeing how injuriously this agent has acted upon puppies, and also how in- 

 effective for good it has proved in our hands in cases of Oxyurides, its 

 employment in young Ostriches seems contra-indicated. 



But there is another practical phase of this question of great interest. 

 It appears to me that these epidemics form, as it were, by-way phenomena 

 of the " struggle for existence." In this view they are most instructive. 

 This Ostrich epizooty is a kind of strongylosis ; and as such it has its 

 counterpart in the trichinosis of swine, in the olulanosis of cats, in t\\ejila- 

 riasis of man, and so forth — all these disorders representing so many 

 special forms of helminthiasis. In every case we see a multitude of lili- 

 putian creatures battling for their own existence. The war is carried on 

 at the expense of the victims infested ; and when, as in the instance before 

 us, the parasites become abnormally prodigious in number, then the bearer 

 or victim is injured. In other words, the invaded territory suffers from 

 overcrowding and multiplied Avounds. Of course, amongst avian, as also 

 among mammalian victims, the smaller and younger hosts suffer more 

 readily than adults. Thus lambs perish more quickly than sheep, colts 

 than horses, chicks than their parent birds. In extreme cases no animal, 

 whatever its size or age, can long withstand the assaults of certain kinds 

 of internal parasites, armed as they not unfrequently are with boring 

 weapons. Thus also, as has been recently shown in my paper on the para- 

 sites of Elephants, comparatively small Entozoa are often as effective for 

 mischief as the larger species. 



DESCEIPTION OF PLATE IV. 



Figs. 1 & 2. Male and female Strongyhis Douglassii. X 65 diameters. 

 3 & 4. Caudal extremities of the same. X 260 diam. 

 a, head ; h, oesophagus ; c, chylous intestine, c', middle, and e", lower ends of 

 the same ; d, rectum ; e, anus ; /, hood and raj's of the male ; g, spicules ; 

 h, sheath ; i, vas deferens ; j, testis ; Ic, Jc', anterior ray-divisions ; I, antero- 

 lateral ray ; m, in', middle ray-divisious ; n, posterior lateral ray ; o, posterior 

 ray of the right lobe ; o', branches of the posterior ray of the left lobe ; p, vulva 

 of the female ; q, upper uterine horn ; r, tuba ; s, ovarium, and s', upper ovarian 

 caecum ; t, fold of lower uterine horn ; 2i, cixcal end of the lower ovarium ; 

 V, ovum ; iv, embryo ; x, caudal papillse of the female ; y, oblique skin-folds of 

 the male ; z, tr;msT«rse cutaneous striaj ; z', longitudinal muscle-cells ; z", re- 

 tractor muscle of the sheath of the male spicule. 



