364 The Clam-Worm. [April, 
To the naturalist who uses the microscope, an old marine 
aquarium is fruitful of interesting minute forms of life, both 
plants and animals. This is certainly true of the micro-alge. I 
observed one day what seemed to me a new form of alge, little 
clusters of a deep orange color on the sandy floor of the aqua- 
rium. Each bunch was hardly more than an eighth of an inch in 
diameter. Some of the little cylinders of which a cluster was 
composed were put under the microscope. There was not the 
slightest appearance of any cell structure, nor even the presence 
of any distinct protoplasm. They were granular in composition, 
but there was no sac or case. They had something of the look, 
size excepted, of the casts in Bright's disease. These little tufts 
of tiny orange-colored cylinders kept on increasing. When two 
or three days old they turned white. I noticed that they were all 
in proximity to the burrows of the Nereids. They proved to be 
their excreta—enteric casts of their imperfectly digested food. 
That deep dull orange was still a puzzle, for when freshly cast 
these excreta were exactly the color of the calcareous crust which 
covers the horny axis of some of the sea-fans, Gorgonia. It was 
noticeable that since the beef diet had been begun, the Ulva was 
let entirely alone. 
But there arose a famine in the land. No fresh beef could be 
got. Of course the Nereids could go back to the sea-lettuce, but 
they chose to let it alone. From “pickings” they turned to 
“leavings,” or perhaps more correctly from “ primes” to “ mid- 
dlings.” Thanks to the gentle Cowper whose Task supplies the 
word befitting ears polite—every “ stercoraceous heap” was soon 
eaten'up! Our pretty Nereis, then, has a threefold appetency— 
since it is by turns a vegetarian, a carnivore, and even an auto- 
stercophaga ! an eater of its own casts. 
But such things are found in higher quarters. Dr. Rau, in his 
_ translation of the Jesuit Baegert, says of certain California tribes 
now extinct, that in its sgason they almost lived upon the fruit of 
the pitahaya, and when that gave out they were reduced to short 
rations. Says the missionary : 
“In describing the pitahayas I have already stated that they 
contain a great many small seeds resembling grains of powder. For 
some reason unknown to me these seeds are not consumed in the 
Es dca cates but _pass off in an undigested state, and in order to save 
a them the natives collect during the season of the pitahayas that 
