GRANTIA CILIATA Fabricius 



Material. Grantia ciliata is very common on the Atlantic 

 Coast. It is found in shallow water just below the low tide mark. 

 Specimens intended for general study as well as for sections 

 showing the arrangement of spicules, should be preserved in 

 alcohol. Specimens intended for microscopic study must be 

 preserved in a special manner. The best method is that of 

 Minchin. It consists in preserving the specimens in the place 

 where they are collected. The collector should take with him a 

 i% aqueous solution of osmic acid, distilled water and Ranvicr's 

 picrocarmin. As soon as the specimens have been brought to the 

 surface they must be plunged into a mixture of equal parts of 

 osmic acid and sea water. After five minutes the specimens must 

 be washed in several changes of distilled water and allowed then 

 to remain for two hours in picrocarmin. They are then ready to 

 be washed again in distilled water and to be transferred into 

 alcohol. Before imbedding the specimens must be decalcified 

 by any one of the usual methods. The sections may be stained 

 for five minutes in a solution composed of one part of i% aqueous 

 solution of nigrosin and nine parts of a saturated aqueous solu- 

 tion of picric acid. Every student should receive for study one 

 alcoholic specimen and the following four prepared slides: a 

 transverse section through an alcoholic specimen, not stained; 

 spicules isolated by boiling in a solution of potassium hydrate; a 

 transverse section through a decalcified specimen preserved by 

 the method of Minchin; a tangential longitudinal section through 

 a similar specimen. 



Descriptive Part 



Grantia ciliata is a common representative of the Phylum 

 Porifera and belongs to the group of calcareous sponges. Unlike 



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