12 BBITISH COPEPODA. 



condition for many years eternally for anything I 

 know to the contrary without the trouble of cement- 

 ing round the edges of the glass cover. The formula 

 which I habitually use is given below.* Before 

 dissecting Copepoda for microscopic examination they 

 should be macerated for a few hours in a solution of 

 caustic potash ; the fatty and granular tissues are by 

 this means removed and the details of structure 

 rendered clearly visible; the dissection is easily per- 

 formed under the microscope with fine needles, either 

 with or without the help of an erector. 



The nomenclature of the body segments and append- 

 ages of the Copepoda, as of the Crustacea in general, 

 has been somewhat confused by the variety of terms 

 applied to the same part by different authors It is, 

 therefore, necessary to explain the application of the 

 terms which I have here adopted. This will be 

 understood by an examination of the table, at p. 14, 

 which shows the names used by some recent writers 

 on the Entomostraca for the appendages of the first 



* Take any quantity of Nelson's gelatine, and let it soak for two or 

 three hours in cold water which has previously been saturated with 

 arsenious acid ; pour off the superfluous water, and heat the soaked 

 gelatine until melted. To each fluid ounce of the gelatine add one 

 drachm of alcohol and mix well ; then add a fluid-drachm of the 

 white of an egg ; mix well while the gelatine is fluid, but cool. Now 

 boil until the albumen coagulates and the gelatine is quite clear. 

 Filter through fine flannel, and to each fluid ounce of the clarified 

 gelatine add six fluid drachms of Price's pure glycerine, and mix well. 

 (' Carpenter's Microscope and its Revelations/ 3rd edition, p. 775.) 



It is worth notice that this preparation is injurious to calcareous 

 structures, such, for instance, as the spicules of Echiuodermata, these 

 being in a comparatively short time completely dissolved by the 

 glycerine. If used for preparations of this kind the glycerine should 

 be omitted. 



