1893.] Eggs of Pityophis Melanoleucus. 879 
Mr. Philip P. Calvert, who was present at the excavation of 
the eggs, furnished me with facts relating to their position and 
surroundings. They occupied an enlargement of the tunnel 
6-8 inches below the surface, where they were massed together 
in a single coherent eluster—the shells being very firmly 
cemented together wherever they came in contact. Ten eggs 
in all were found, three of which were detached from the mass 
in removal; the remaining seven are shown in Fig. 1 (from a 
sketch by Mr. v. Iterson, the laboratory artist) which I am 
able to reproduce here through the kindness of Dr. Ryder. 
The eggs are of irregular ellipsoidal shapes, varying much in 
size and proportions, and exhibiting, as a result of the various 
pressures to which they have been subjected, irregular depres- 
sions and protuberances. In size they range from 50x37 mm. to 
64x 45 mm., a long narrow egg measuring 61x35 mm., and a 
short broad one 60x44 mm. The average measurement of the 
seven is 59x41 mm., exhibiting a mean variation in length of 
4 mm., and in breadth of 38 mm. The variation in size is due 
chiefly, if not solely, to the variable amount of yolk present. 
In the hope of raising some of the young, several of the eggs 
were placed in a box of dampened sand and stood in a sunny 
spot: but on being opened after three weeks the embryos were 
dead, and development interrupted at the point that had been 
reached on Aug. 4, when I received the eggs. 
When fresh, the egg-shell was flexible and elastic, and of a 
very tough parchment-like character; and was very tensely 
and firmly stretched over its contents; but after a few days' 
exposure to evaporation, it became somewhat loose and 
wrinkled. 
Its structure is interesting. Externally there is a thin in- 
crustation of calcareous matter, which impregnates only the 
outer layers of the matted fibres of which the shell is mainly 
composed, and which appears to be present chiefly in the form 
of minute crystals and hexagonal plates. Over the greater 
part of the surface the calcareous crust is minutely cracked 
into elongated polygonal and irregularly lozenge-shaped areas, 
resembling the modern “crackle-ware” or the surface of old 
porcelain (Fig. 2). This appearance is particularly noticeable 
59 
