The Sloughi is a North African breed of dog, specifically a member of the sighthound family.
 It is found mainly in Morocco, which is responsible for the standard, and may be found in smaller numbers elsewhere in North Africa.
The Norfolk pigeon or Norfolk Island pigeon (Hemiphaga novaeseelandiae spadicea), sometimes called a wood quest, was a subspecies of the New Zealand pigeon that inhabited Norfolk Island.
 It went extinct around the turn of the 20th century.
The Tweed Water Spaniel, or Tweed Spaniel, is a breed of dog extinct since the 19th century.
 It is best known for being involved in the early development of the modern Curly Coated Retriever and Golden Retriever breeds of dogs.
 They were described as a generally brown athletic dogs from the area around Berwick-upon-Tweed near the River Tweed and close to the Scottish Borders.
 A type of water dog, the breed was not well known outside the local area.
 This breed may have been created by crossing local water dogs with imported St. John's water dog, another breed which is also now extinct.
The American Cocker Spaniel is a breed of sporting dog.
 It is a spaniel type dog that is closely related to the English Cocker Spaniel; the two breeds diverged during the 20th century due to differing breed standards in America and the UK.
 In the United States, the breed is usually called the Cocker Spaniel, while elsewhere in the world, it is called the American Cocker Spaniel in order to differentiate between it and its English cousin, which was already known as "Cocker Spaniel" before the American variety was created.
 The word "cocker" is commonly held to stem from their use to hunt woodcock in England, while "spaniel" is thought to be derived from the type's origins in Spain.
The Saint-Usuge Spaniel (or Épagneul de Saint-Usuge) is a breed of Spaniel originating in the Bresse region of France.
 The breed has origins dating back to at least the 16th century, but was nearly extinct by the end of World War II.
 Through the efforts of Father Robert Billard, the breed was resurrected during the second half of the 20th century; its national breed club was founded in 1990.
 The breed was recognised by the Société Centrale Canine (French Kennel Club) in 2003.
The French Spaniel (Epagneul Français) is a breed of dog of the Spaniel-like setter.
 It was developed in France and Canada as a hunting dog, descended from dogs of the 14th century.
 Popular with royalty during the Middle Ages, it nearly became extinct by the turn of the 20th century but was saved by the efforts of Father Fournier, a French priest.
 One of the largest breeds of Spaniel, it typically has a white coat with brown markings.
 It is a friendly breed that has few health issues, but can be affected by a syndrome called acral mutilation and analgesia.
 The breed is recognised by Canadian and international kennel clubs but not by The Kennel Club (UK).
 The American Kennel Club has included the breed in its Foundation Stock Service, the first step to full recognition.
The Toy Trawler Spaniel is an extinct breed of Spaniel which physically was similar to the King Charles Spaniel of the 16th century.
 It is considered to have descended from the original King Charles Spaniel, and the older variety of Sussex Spaniel.
 It was originally used as a sporting dog, but became used as a toy and show dog.
 It was considered to be on the verge of extinction by 1920.
 A preserved specimen is kept in Tring at the Natural History Museum.
The Norfolk Spaniel or Shropshire Spaniel is an extinct breed of dog since the early 20th century.
 It was originally thought to have originated from the work of one of the Dukes of Norfolk, but this theory was disproven after being in doubt during the later part of the 19th century.
 The term was used to designate springer type spaniels that were neither Sussex nor Clumber Spaniels, and attempts were made to use it to specify a breed that would later become known as the English Springer Spaniel.
The white-throated rail ("Dryolimnas cuvieri") or Cuvier's rail is a species of bird in the family Rallidae.
 It is found in Comoros, Madagascar, Mayotte, and Seychelles.
 A flightless subspecies, "Dryolimnas cuvieri aldabranus" (Aldabra rail), inhabits Aldabra, while another, "D. c. abbotti" (Assumption rail), from Assumption went extinct in the early 20th century due to introduced predators.
The Picardy Spaniel is a breed of dog developed in France for use as a gundog.
 It is related to the Blue Picardy Spaniel, and still has many similarities, but the Picardy Spaniel is the older of the two breeds.
 It is thought to be one of the two oldest continental spaniel breeds and was favoured by the French nobility, remaining popular for hunting after the French Revolution due to its weather resistant coat that enabled it to hunt in a variety of conditions and terrain.
 However its popularity waned following the influx of English hunting breeds in the early 20th century.
 Slightly smaller than an English Setter but larger than most of its spaniel cousins, it has no major health issues although as with many breeds with pendulous ears, it can be prone to ear infections.

Question: Which dog breed nearly went extinct in the 20th century, the Sloughi or the Saint-Usuge Spaniel?
Answer: The Saint-Usuge Spaniel