The echidna is a monotreme, which is the extremely small subset of oviparous mammals.

And though it might be thought that all animals who have lungs do cough; yet in cataceous fishes, who have large and strong lungs, the same is not observed; nor yet in oviparous quadrupeds: and in the greatest thereof, the crocodile, although we read much of their tears, we find nothing of that motion.

Until fairly recently, no female Somniosus had been observed to be carrying embryos, so it was assumed that this was an oviparous species.

Oviparous

Meaning

Adj

Origin