BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [20] 



beginning operations, see that the specimens of Cladactis and Cereactis 

 are perfectly sound and especially that they are not torn or cut, other- 

 wise when they are placed in alcohol the liquid contents of the body 

 will exude through the rents. Large specimens of Ceriant/ms are fixed 

 with acetic acid and immediately afterwards are suspended in weak 

 alcohol by means of a thread fastened around the column near the 

 base. A few gentle shakes may be needed to adjust the tentacles. It 

 is not necessary to suspend the small speciuijens. 



Actinia equina and A. cart are treated with boiling mixture of 

 sublimate and acetic acid, followed by chromic acid of one-half of 1 per 

 cent for hardening. Frequently success has been attained with the 

 first of these species by lifting it gently with a spatula from the bPiaker 

 in which it is expanded and immersing it in a saturated solution of 

 sublimate. 



Edwardsia is slowly narcotized by dropping from time to time a few 

 drops of 70 per cent alcohol into the sea water in which it is. It is 

 then killed with hot saturated sublimate. Success depends upon the 

 complete loss of sensitiveness, which may be tested by touching the 

 tentacles with a needle point. 



Certain species of Polythoa are very difficult to prepare. Even with 

 reagents of rapid action they will have the body well distended and 

 often only a portion of the tentacles outside the disk. One species 

 which lives in sponges and among calcareous algse (probably a variety 

 of P. axinellce) is prepared very successfully with boiling saturated 

 sublimate. 



Larvfe of the Actinians are killed with saturated sublimate or with 

 chrom-acetic No. 2. 



MADREPORAKIA. 



Astroides calycularis is allowed to remain overnight in a beaker 

 filled with clear sea water. The following morning usually shows the 

 polyps in full distension. Then, after turning oft" a portion of the 

 water (enough to leave the animals barely covered), kill them with a 

 solution of boiling sublimate and acetic acid in volume equal to that of 

 the sea water, and immediately afterwards transfer the colony to 35 per 

 cent alcohol, making an iujection of the alcohol into each polyj) to keep 

 it well distended. At each change of alcohol up to 70 per cent make a 

 similar injection, and be sure to test the final solution with tincture of 

 iodine to see that the sublimate has been eliminated. 



Garyophyllia, Dendrophyllia, and Cladocora are fixed with boiling 

 saturated sublimate, but it is very difficult to prepare them with the 

 polyps in perfect expansion on account of their great contractility and 

 also by reason of the extreme delicacy of their walls. 



HVDKOMEDUS.K. 



The HydromeduSfb in general are very delicate forms, which are 

 easily injured and which quickly decompose, hence it is necessary to 



