[31] THE PRESERVATION OF MARINE ANIMALS HOVEY. 



The Nematodes, free and parasitic, are killed with saturated subli- 

 mate or with Kleiueiiberg's liquid. 



ChcetognatJia. — These are very well treated in the mixture of sulphate 

 of copper and sublimate and in the chrom-osmic mixture. 



Gephyrea — Sipiincuhis is killed with chromic acid of one-half of 1 per 

 cent or even weaker, in which the tentacles usually, but not always, 

 expand before death. The animal, after being narcotized with chloral 

 hydrate of 0.1 of 1 per cent in sea water, dies with tentacles distended. 

 Both methods are good, but sometimes a i)ortion of the animal remains 

 contracted, and sometimes during the process the skin in front breaks 

 and allows all the perivisceral liquid to escape, with resulting distortion 

 of the body. 



Fhascolosom.a may be jDlaced in alcoholized sea water and allowed to 

 remain there until dead (three to six hours). Fhoronis is allowed to 

 remain half an hour in alcoholized sea water and then is killed with boil- 

 ing saturated sublimate. With the large specimens of BonelUa it is best 

 to wait until the proboscis has become well distended and then seize the 

 body of the animal with one hand and the extremity of the proboscis 

 with a pair of forceps so that it can be kept distended. Then quickly 

 immerse the whole in Kleinenberg's liquid in the wax-bottomed tray, 

 and, always keeping the animal stretched out to prevent contraction, 

 wait until it dies. After lying for an hour in this solution the transfer 

 to alcohol may begin. Small Bonellias are narcotized in alcoholized sea 

 water and fixed in weak alcohol. The very small specimens of these 

 Gephyreans are very well killed with hot sublimate. The pelagic larvae 

 of EcJiiurus are well fixed by allowing them to lie for some minutes in 

 the mixture of sulphate of copper and sublimate. 



Hii'udinei, Pontohdella, and BranclielUon are killed in chromic acid of 

 one-half of 1 per cent. If in doubt about worms of this family, hot satu- 

 rated sublimate may be recommended for use. In any case long speci- 

 mens must be straightened and hardened in the wax-bottomed tray. 



CJicetopoda. — Many of these, if placed in a fixing fluid which is too 

 energetic in action, contract greatly and twist out of shape, and many 

 of them break to i)ieces, so that an idea of the natural form is lost. 

 This trouble has been obviated by very gradually pouring over the 

 surface of the sea water in the crystallizing dish a stratum of a mix- 

 ture of glycerin, 1 part, 70 per cent alcohol, 2 parts, and sea water, 

 2 parts. This stratum will slowly diffuse throughout the water, and 

 after some hours the animals will be narcotized and will remain fully 

 distended, if transferred to alcohol. 



Experience at the station has shown that alcohol alone suffices for 

 the treatment of these worms. Instead of the mixture just described, 

 one may add to the sea water 5 per cent of absolute alcohol and let 

 the animals remain therein until they have lost motion, an operatic 

 which varies from two to twelve hours for the different siDecies. It 

 a good plan not to allow these worms to become entirely dead in th 



