Answer: spines

AnswerCrossword Clue
SPINESFeatures of hedgehogs
SPINESSharp plant parts
SPINESBook stiffeners
SPINESBook parts
SPINESPorcupine's protection
SPINESTomes' strongest parts
SPINESBacks of books
SPINESSea-urchin features
SPINESPlaces for titles
SPINESEchidna features
SPINESVertebral columns
SPINESLibrary patrons read them
SPINESBookcase lineup
SPINESThistle features.
SPINESCactus features
SPINESMollusks lack these
SPINESSea urchin's protection
SPINESBackbones of books
SPINESThings seen on a bookshelf
spinessharp rigid process on an animal as
spinesstiff pointed plant process
spinesspinal column
spinesicule
spinesSPINE, the vertebral column
spinesstiff unsegmented fin ray of a fish
spinespointed prominence on a bone
SPINESPlaces for book titles
SPINESBookbinder's pieces
SPINESBook backs
SPINESBackbones
SPINESThey're seen on bookshelves
SPINESSpots for authors' surnames
SPINESQuills
SPINESTitle holders?
SPINESProcupine's protection
SPINESThorns
SPINESNovels have them
SPINESBookshelf lineup
SPINESParts of books
SPINESThey've got your back