Here's why:
* Siamese is a breed of cat, specifically known for its distinctive coloring.
* Manx is another breed of cat, known for its short or absent tail.
* Clydesdale is a breed of horse, known for its large size and distinctive feathering on its legs.
* Shetland Pony is a breed of horse, known for its small size.
The analogy establishes a relationship between breeds within the same animal category (cats and horses). Just as Siamese and Manx are both cat breeds, Clydesdale and Shetland Pony are both horse breeds, with contrasting physical characteristics (large vs. small).