About the style,
Tuscans can be described as decorative display faces with characteristics that usually include one or more of the following: bi- or trifurcated (branched) serifs or mannered stroke terminations (pointed, rounded, concaved, chiseled, wedged…); an active, energetic contour; and medial decoration. Tuscans can also be additively ornamented (shades, shadows, fills, patterned interiors…).
The whole history at the Hamilton Wood Type & Printing Museum
... The concave slab serif of the American Tuscan was further modified with notches added to the capline and baseline to produce bifurcations with a symmetrical spur (typically referred to as medial spurs) was added to the middle of the letterforms.
The origin dates from the nineteenth century when the typography leaves the printed paper to move to large posters with giant letters made in wood types simulating the store signs. The short reading allows more attention to the ornamented strokes than readability, therefore, the most ornate were the most popular.
There are more examples in this answer
There's also a "median spurs" tag at myfonts.com advanced search