382 PARASITES OF ANIMALS 



fatal epidemic affecting the mules of the Mauritius in 1876 can 

 scarcely fail to have observed that the worm called Ascaris 

 vermicular is by Mr Bradshaw is none other than our Sp. 

 megastoma. The description of the tumours as " reticulated " 

 sufficiently explains their honeycomb- like appearance, but I 

 think that the expression "alveolar" would better convey their 

 true pathological character. Mr Spooner Hart compared these 

 structures, which he terms " abodes," to mole-hills, but there 

 is no good ground for supposing that the wanderings of the 

 parasites are in any sense comparable to the burrowings of the 

 mole. In like manner the expression " nidus," employed by 

 Mr Bradshaw, though suggestive of their nest-like appearance, 

 is to some extent misleading, as it implies that the worms form 

 a nide or brood. Possibly, it may turn out that all the nema- 

 todes in each tumour have been bred in the spot where they are 

 found, but hitherto they have only been seen in the adult state. 

 Earlier stages of growth should be diligently sought for. 

 Widely dissimilar as the two maw-worms are, it would not 

 greatly surprise me to learn that Sp. megastoma and 8. micro- 

 stoma are dimorphic conditions of one and the same entozoon. 

 At all events, Ercolani's determination of the relations subsist- 

 ing between Ascaris inflexa and A. vesicularis suggests a possible 

 analogy of this kind. I may mention that the male Spiroptera 

 megastoma reaches nearly one third and the female one half 

 of an inch in length. A constriction separates the head 

 from the body. The mouth is surrounded by four thick 

 horny lips, the dorso-ventral pair being the larger. The tail 

 of the male is spirally twisted, and furnished with lateral 

 bands supported by three or four ribs. It carries two curved 

 spicules of unequal size. There are five pairs of caudal 

 papillae, the tail being bluntly pointed in both sexes. The 

 vulva of the female is placed about i" below the head. The 

 eggs are linear or very narrow, and furnished with thick shells. 

 According to Sonsino, who found Sp. megastoma in five out of 

 sixteen Egyptian horses, the verminiferous growths are usually 

 seated near the pyloric end of the stomach, as many as four 

 tumours occurring at one time. Neither Sonsino nor any other 

 observers already quoted appear to think that these morbid 

 changes in any way interfere with the healthy performance of the 

 gastric functions. However, I am of opinion that at least one 

 recorded fatal case of parasitism, producing rupture of the 

 stomach, affords an instance, however rare, of the injurious 



