MARINE BIOLOGICAL STATION ON PUFFIN ISLAND. 55 
Dr. Hanitsch has commenced some researches upon the 
minute structure of some of the Mollusca. 
Mr. Thompson has taken charge of the surface life of 
the sea, and has been specially investigating the Copepoda, 
a group of small Crustacea. 
These animals and many others, including the larval 
stages and other young forms of vast numbers of animals 
which are fixed or live at the bottom of the sea when fully 
developed—such as barnacles, crabs, molluscs, annelids, 
polyzoa, star-fishes, sea-urchins, and zoophytes—are found 
swimming at or near the surface of the sea, and form a 
most important part of the marine Fauna. ‘They are 
captured by means of the tow-net, a long conical bag of 
canvas, silk-gauze or strong muslin, attached to an iron 
hoop about a foot in diameter, and tapering to a closed end, 
into which a small glass bottle or tube may be inserted if 
required. The tow-net is let down over the stern of the 
steamer when going slow, and is dragged along just below 
the surface of the water for half an hour or so. It is then 
pulled on board and turned inside out into a glass vessel of 
sea-water, when the minute organisms which have been 
captured become detached from the inner surface of the 
net and float about in the water, from which they can then 
be removed by a fine glass dipping tube and placed in a 
watch-glass of sea-water under the microscope. 
Generally the contents of the tow-net are very largely 
composed of Copepoda, small Medusx or jelly-fishes, and 
larval stages in the development of other animals ; but at 
certain times Mr. Thompson has noticed* the presence 
of an extraordinary number of small spherical gelatinous 
* See “Nature,” for 23rd July, 1885, under heading ‘‘ Foul Water.” 
Mr. Shrubsole has noticed the same condition off Sheerness, and Professor 
McIntosh describes it also as occurring in St. Andrew’s Bay (Ann. and Mag. 
Nat. Hist., Aug., 1887). 
