Several moultings take place in the asexual condition. Other views have been advanced as to the development of the sclerostomata. Colin believed that the ova deposited in the ducts of the mucous glands and in the perforations made by the parasite in blood-sucking, hatched in this situation and the embryo at once encysted itself in the mucosa. Leuckart imagines that the embryo found in the fæces or in water outside the body of the soliped, should pass through an intermediate host before it can return to gain sexual maturity in the horse. But no evidence of the existence of such intermediate host is furnished, and the encysted intestinal worms show no indication of a special development which would have been accomplished in such host. Willach holds to a hermaphrodite stage passed in the intestine of the soliped. He found in the bowel small worms apparently related to the sclerostomata by the appearance of the head and the caudal membrane, but not exceeding three to five lines in length. Some were evidently females and contained not only eggs with soft shells, but in one case embryos. Others had the caudal membrane of the male, yet contained also a few eggs. There is no vulva and the embryos escape by rupture of the oviducts. These embryos he supposes are developed in the same host into the familiar mature sclerostomata. Whatever may be said of those alleged modes, the first described series of changes and migrations may be taken as the usual and regular method of development. =Pathogenesis.= _Lesions._ These embrace perforations of the mucosa, cysts, aneurisms, embolisms and congestions. =Irritation of the mucosa.= The adult worms, like so many leeches are continually biting and sucking blood from the mucosa and when present in large numbers, hundreds, thousands, or a million create an aggregate of irritation which may determine violent indigestions and congestions. =Verminous Cysts.= These are like a pin’s head, a pea or hazel nut, containing the asexual worm in a mass of purulent debris, or if empty, presenting a small orifice where it made its exit.