These illustrations come from the International Pictorial Treasury of Knowledge book series, published in 1960. The title of this book is Life and its Marvels: Plant, Animal, Human. I picked up four books from the series at a garage sale a few years ago. The illustrations in these books are fantastic and sometimes strange. The layout for all of the books features a page of text across from a page of related illustrations. The caption for the image page is at the bottom of the text page. I will have more from this series later in the project.
Olfactory organs
Aquatic nests
Different types of stomachs