Archaeopteryx of "Archaeopteryx" bones appear poorly vascularized; in living vertebrates, poorly vascularized bone is correlated with slow growth rate. They also assume that all known skeletons of "Archaeopteryx" come from juvenile specimens. Because the bones of "Archaeopteryx" could not be histologically sectioned in a formal skeletochronological (growth ring) analysis, Erickson and colleagues used bone vascularity (porosity) to estimate bone growth rate. They assumed that poorly vascularized bone grows at similar rates in all birds and in "Archaeopteryx". The poorly vascularized bone of "Archaeopteryx" might have grown as slowly as that in a mallard (2.5 micrometres per day) or as fast as
Specimens of Archaeopteryx totaling 1,756 Solnhofen specimens - was purchased the following year. In this way the London Museum came to acquire a truly important collection of fossils, many of them quite rare or undescribed at the time. Wellnhofer remarks that it was likely not the price that kept the Bavarian State Paleontological Collection in Munich from acquiring the fossil, but rather the hesitating attitude of Andreas Wagner which delayed any action. Following Wagner's death in 1861, negotiations with Häberlein certainly would have been all the more difficult. In the wake of this important transaction of the first "Archaeopteryx" body fossil, many German