Horse outward similarity is an unreliable measure of relatedness. Besides the horse, there are six other species of genus "Equus" in the Equidae family. These are the ass or donkey, "Equus asinus"; the mountain zebra, "Equus zebra"; plains zebra, "Equus quagga"; Grévy's zebra, "Equus grevyi"; the kiang, "Equus kiang"; and the onager, "Equus hemionus". Horses can crossbreed with other members of their genus. The most common hybrid is the mule, a cross between a "jack" (male donkey) and a mare. A related hybrid, a hinny, is a cross between a stallion and a jenny (female donkey). Other hybrids include the zorse,
Equus Press Equus Press London- and Prague-based Equus Press (Écriture en Quête d’Usage), founded in 2011, focuses on publishing experimental Anglophone writers and is concerned primarily with English language writing from outside of normal English-speaking areas. Since it was established, Equus Press has published the works of such as authors Louis Armand, Thor Garcia, Ken Nash, and Damien Ober. In April 2013, Equus Press published "Louis XXX" (Georges Bataille) in a translation by Stuart Kendall. 2014 saw the release of "Cairo" (Louis Armand), a novel shortlisted for the 2014 "Guardian" Not-the-Booker Prize, and the novel "Doctor Benjamin Franklin’s Dream America" (Damien Ober)