302 § ANNUAL REPORT SMITHSONIAN INSTITUTION, 1946: 
Carbohy- 
Crop Proteid Fat into Ash 
Percent Percent Percent Perecnt 
Ordinary meadow: hay -s--s--+ 4-24-22 8.7 1.7 83. 6 5.8 
Good ineadow Way. cnr skeen ene: a 13.6 3.2 75.0 8.2 
(5) 2 1: ll a age rea tne 11.15 2.45 79. 30 7. 00 
DIACONI Se eee ne eee aan e ee ewes See 10.0 2.8 22.0 65.0 
Peridinians) 9. te oO) 5 ee ee 13.0 1.3 80. 5 5.2 
PAIN OTEPO me 5- ata a= SE ee ee a a ee 11. 50 2.05 61. 25 35. 10 
MARINE HERBIVORES AND CARNIVORES 
Any attempt by man to harvest directly the microscopic plant life 
forming the meadows of the sea would be as impracticable as to 
grow forage hydroponically for meat production. Fortunately, this 
will never become necessary, as nature has provided herbivorous ani- 
mals specifically adapted to graze those vast oceanic fields and to con- 
vert their forage crop into animal food acceptable to the higher and 
more carnivorous forms of marine life, as well as to man himself. 
The marine herbivores, as well as the marine carnivores that prey 
on them, are well adapted to moving about in their watery environ- 
ment. All are motile to a greater or less degree; the protozoa or 
single-celled animals are flagellated or ciliated, as are the larvae of 
most marine invertebrates, or provided with pseudopodia; some, like 
the jellyfish, squids, and octopi, are after a fashion jet-propelled ; most 
crustacea have oar- or paddle-feet for locomotion when they are not 
strictly sedentary or ambulatory forms. The marine vertebrates, as a 
rule, have powerful tails to drive them forward, assisted by fins and 
flippers used also for balancing. Most, if not all, of the various adap- 
tations for facilitating flotation in plants are repeated in one form or 
another in the animal life of the sea: expansion of the body; the 
development of bristles, setae, and horns; the storage of oil droplets 
and fatty material; and inclusion of gas or air in the bladders of certain 
fishes. 
The number of grazers on the meadows of the sea is also a measure 
of the productivity of those fields. The principal grazers are the 
Crustacea, foremost among which in numbers and in consumption of 
phytoplankton are the small relatives of the shrimps known as the 
copepods. Various estimates have been made of the abundance of 
copepods. The North Sea is believed to support from a quarter of a 
million to a million per square meter of surface. For the West Baltic 
Hensen estimated a total of something like 80,000 per cubic meter, or 
80 to 100 billion to each square mile of surface. Gulf of Maine aver- 
ages reported by Bigelow ran from 6,000 to 500,000 per square meter 
of surface. His record catch of copepods was obtained in the course 
of a 15-minute vertical haul, July 22, 1916, from 40-0 fathoms. The 
net on this occasion yielded about 6 quarts of large calanoid copepods, 
