1002 Marvels of the Universe 
similarity, in their physical features and climatic conditions, because we know that closely-allied 
species of that class are adapted to extraordinarily diverse surroundings. But since reptiles, unlike 
mammals, have very limited powers of temperature adjustment, the heat of the blood rising and 
falling with that of the medium in which they live, it may be assumed that in Triassic times, when 
Pariasaurus flourished, the climates of Northern Europe and Southern Africa were, to all intents 
and purposes, the same. Moreover, although it is possible these monsters hibernated like Euro- 
pean reptiles of the present day, the apparent necessity nowadays for tropical or sub-tropical heat 
in developing reptilian bulk perhaps justifies us in thinking that the conditions under which Paria- 
saurus lived, whether in the northern or the southern hemisphere, were such as to produce and 
maintain a perennially luxuriant vegetation. Thus a study of one isolated type of extinct animals 
may throw a flood of light upon the conditions of existence in two remote parts of our planet, 
perhaps a score or more of millions of years ago. 
Tinks, SCAILIL©O 12 
BY BERNARD C. WHITE. 
THERE is no class of shell which has such variety and 
briluancy of colour as the Scallop. Some species are 
glittering orange. Another species, which is particu- — 
larly lovely, glows with red and purple; another is 
covered with crimson and white ribbon patterns, while 
others are noticeable for their delicacy—pale pink, 
with dainty white frills; pale saffron, with a pink 
flush ; lemon-coloured Scallops, and Scallops of 
daintiest green. But description fails to paint their 
glories, and if the reader desires to realize their 
beauty, he cannot do better than visit the Shell Gallery 
of the Natural History Museum, where he will find 
them under their family name of Pectinide, a group of 
dazzling colour. 
It should be noticed that the shell of a Scallop 
covers a large superficial area, but is comparatively 
thin and light. Such a combination of qualities would 
Ket eey SiS een Ce Main: not, under ordinary circumstances, go for strength, 
Te OG ma talnc bee iee ant eee Ee and the inmate of the shell would have little chance 
insecUlaPpearedassaubcautiiulaty: of withstanding the stress of the ocean. 
But Nature has provided for such a contingency. It will be noted that except in abnormal 
cases the shell of the Scallop is marked with hollow ribs, which vary in number according to the 
species, and run from the beak to the margin of the shell. It is these ribs which give additional 
strength to the shell’s light structure. But why is it necessary that the shell should be light ? Well, 
the Scallop, differing from all other bivalves, takes swift journeys through the water. It does this 
by rapidly opening and closing the valves of the shell, and if it is to pursue this habit, its shell must 
necessarily be less solidly built than that of a sedentary mollusc. 
This power of locomotion in the Scallops is a fact not as generally known as it should be, even 
among those whose daily business is in the shallow waters of our coast. Mr. Step has told of the 
astonishment exhibited by a couple of fishermen to whom he had shown some Scallops in active 
fight. The men included oyster- and scallop-dredging among their avocations, and thought they 
were being imposed upon when he spoke of Scallops flitting through the water. When some small 
species of Pecten were disturbed and caused to pursue their zigzag flight before the eyes of the 
