RESPIRATORY ORGAN • FREE-TRANSLATOR.COM • Definition of Respiratory organ

... successive chambers of the orthoceratidae. Nor are parts of a series less serial, because arranged spirally, as in most gasteropods. Mr. Spencer observes of the molluscous as of the vertebrate animal, "You cannot cut it into transverse slices, each of which contains a digestive organ, a respiratory organ, a reproductive organ, &c."[172] But the same may be said of every single arthropod and annelid if it be meant that all these organs are not contained in every possible slice. While if it be meant that parts of all such organs are contained in ...

— On the Genesis of Species • St. George Mivart