[63] THE OYSTER AND OYSTER-CULTURE. 745 
with their claws for something to eat. Worms stick their heads out of 
holes and crevices; sea-urchins stretch out their sucking feet beyond 
the points of their spines and pull themselves slowly up on to a stone; 
a star-fish, with greatly arched back, has fastened itself about a mussel 
in order to suck it out of its shell; and a small fish has stationed itself 
under an open oyster and snaps up the embryos as they come from 
the shell.* Of this life of the oyster-bank the diver would see little or 
nothing, even if he happened to be a zoologist, for as soon as he had 
descended to the bottom the oysters would shut themselves up, the crabs 
and worms creep out of sight, and the fish swim away. I thus sketch 
this picture of a small portion of the really abundant life of an oyster- 
bank in order to show that one may become really very well acquainted 
with an oyster-bed by means of adredge. It can also be used to estimate 
the thickness of oysters upon a bed, if the distance passed over by the 
dredge while it is taking oysters be measured. In the inspections of the 
Schleswick-Holstein banks, during the last few years, this has been ac- 
complished in the following manner: At those points, where the dredge 
is dropped upon the bed, an empty cask, attached by means of a rope to 
a heavy weight, is cast overboard. The weight sinks tothe bottom and 
holds the cask securely anchored, floating upon the surface of the water. 
-Connected with the rope of the cask is a measuring-line, whichis wound 
upon a roller, and which runs off as long as the vessel is going forward 
and the dredge drags over the bottom. The mouth of our larger dredges 
is one meter in width. Thus, if we let the dredge drag over the bottom 
until 100 meters of line have run off, and find that we then have 50 oysters 
in the bag, we can conclude that one oyster came from every two square 
meters of bed-surface; and if an oyster-bank, the length and breadth 
of which are known, is dredged over in this manner in different diree- 
tions, a foundation is obtained from which to estimate the number of 
oysters upon the bed with certainly as much accuracy and with far 
greater speed and ease than a diver; and when the proportional pro- 
ductiveness of a bed thus examined is ascertained, we can estimate the 
number of oysters which can be taken from the bed without injury to its 
productiveness. 
Practical persons will object to these methods as being too detailed, 
and yet not leading us to a sufficiently high estimate of the number of 
oysters; but they will be obliged to admit that there is no better means 
of finding out, with any degree of certainty, the number of oysters 
upon these banks. <A skillful oysterman, one who has been acquainted 
with the beds for a number of years, will notice, without the use of a 
measuring-line, whether the oyalers lie uuORs the banks in sufficient 
- *An oyster- eae eas ain metton saw, at some oyster- ae ution for ar tificial cult- 
ure, small fish of the genera Gobius and Mullus swallowing young oyster-swermlings. 
He caught the fish, opened their stomachs, and found therein partially digested em- 
bryos. (Report on the oyster-fisheries, p. 87, Nr. 1711.) 
