- Yellowthroat
- Yellow-shafted Flicker
- Yellow-headed Blackbird
- Yellow-breasted Chat
- Yellow-billed Cuckoo
- Yellow Warbler
- Wood Thrush
- Wing of a Bird, Showing the Arrangement of the Feathers
- Wilson’s Warbler
- Wilson’s Snipe
- Wilson’s Phalarope
- White-crowned Sparrow
- White-breasted Nuthatch
- White Pelican
- Warbling Vireo
- Volvox
- Vesper Sparrow
- Upland Plover
- Two deer
- Two cows
- Two cows
- Two children offering hay to cow
- Two calves
- Twisted Lime worm ( Serpula contortuplicata )
- Turkey Vulture
- Tufted Titmouse
- Tree Swallow
- The Wolf among the Sheep. (John x. 12)
- The Wanderoo
- The Skull and Brain-Case of Pithecanthropus
- The Locust
- The Lion
- The Flipper of a Whale compared to the hand of man
- The Elephant, and its young
- The cockroach mite
- The Chief of the Clan
- Tea time interrupted
- Surinam Toad (Pipa Americana) with Young Ones Hatching out of Little Pockets on her Back
- Summer Tanager
- Study of a cat from nature
- Stone lion at the entrance to a temple
- Starling
- Spotted Sandpiper
- Spiny Hermione ( Hermione hystrix )
- Sparrow Hawk
- Song Sparrow
- Snowy Egret
- Snow Goose
- Slate-colored Junco
- Skeletons of the Gibbon, Orang, Chimpanzee, Gorilla, Man
- Screech Owl
- Sacred Bull of Burma
- Ruddy Duck
- Ruby-throated Hummingbird
- Ruby-crowned Kinglet
- Robin
- Ring-billed Gull
- Representative Protozoa associated with cockroaches
- Relationship between a mature plant of Herpomyces stylopygae and the integument of Blatta orientalis
- Red-winged Blackbird