THE MEDUS.E. 1G7 



taken in Dr. Fowler's closing-nets were badly damaged, and many specimens had the 

 ectoderm and endoderm completely rubbed off. I would suggest that these nets be 

 fastened on to a series of hoops, so as to prevent the sides froai coming together when 

 the mouth is closed. 



The speed of towing the net is a very important matter when jelly-fish are wanted in 

 good condition. As a rule, the net is towed too fast. AVhen using my own net, of the 

 size mentioned above, from a rowing-boat, I know that the speed is about right so long 

 as I can comfortably hold the line on one finger. I once tested the pull with a spring 

 balance, and found that a pull of about three pounds was quite sufficient. If one tows 

 too fast the water banks up in front of the net and the animals shoot off to the sides, 

 and most of them pass outside the net. 



When working a tow-net from a steamboat or a sailing-boat there is nearly always the 

 difficulty of regulating the pace of the boat. Even with the sails down or the engines 

 stopped a light breeze soon causes the boat to drift too fast, and then comes a strong 

 pull and a heavy strain which crushes the animals against the meshes of the net. 

 Dr. Fowler has just designed a tow-net to close as the pressure increases. Its design is 

 most ingenious, and its construction is so simple that there is no mechanism to get out of 

 order. I feel sure that this kind of net will be most useful to those who have to work 

 from steamboats or sailing-boats. 



Preserving MedusiB. — The wrong method, and the one which I believe from the appear- 

 ance of specimens is most frequently used, is to strain off the water and then place the 

 whole bulk of the plankton in a small bottle with a little formalin or alcohol. I have no 

 doubt that this method answers fairly well for animals which have a hard coat, or for 

 organisms such as diatoms ; but it is ruinous for a medusa or for any other soft-bodied 

 animal. A medusa treated by this method is either squashed fairly Hat, or is badly 

 contracted and out of shape. It is frequently mutilated and more or less macerated. 

 For the description and identification of medusae it is really necessary that some of tlie 

 specimens should be in good condition. 



When the net is taken on board, the contents of the can should be poured into one or 

 more glass vessels ; the medusae picked out and transferred to another glass vessel, which 

 must be perfectly clean and free from chemicals. At first the medusye are generally in 

 a contracted condition, and if preserved at once they die contracted. It is now best to 

 place the vessel aside for half an hour or a little longer, and, in the meanwhile, look 

 after the other membeis of the plankton. During the interval most of the medusae, 

 unless badly damaged, will have recovered from the shock, and will be seen slowly 

 pulsating and swimming about. If they should be crowded in a heap on the bottom of 

 the vessel, a slow stir round with a clean glass rod indu.ces them to swim and expand. 

 The medusaj may be left in the vessel for two or three hours, if otlier work should be 

 more pressing and important, but an occasional stir roimd is beneficial. If the medusa? 

 after the first half-hour look in a sickly condition, the sooner they are preserved the 

 better ; but if in a healthy condition, there is no need to hurry over the preservation. 



The simplest and quickest method for preserving either a few specimens or several 

 dozen is the pouring of diluted formalin into the sea -water ; but the secret of success 



SECOND SERIES.— ZOOLOGY, VOL. X. 29 



