Late nineteenth-century photography required that subjects remain still for around 30 seconds. This is a brief instant for an adult, an agonizing eon for a child, and generally impossible for a baby who doesn't yet know about time.
In order to make their babies sit still, parents would sit alongside them. But because they didn’t want their parent-y faces to ruin the pictures, they would cover themselves with rugs and drapes and general Grim Reaper garb. The resulting effect is terrifying.
Linda Fregni Nagler has a book about the subject, called The Hidden Mother. She writes that the 1,002 photographs speak to "women’s place in a patriarchal society, where she is figured without an identity of her own." So sure, in addition to being scary-funny, these photos present a serious reflection of gender roles through history. (A similar theme appears in photographer Patty Carroll’s recent series.)