Electric Fire Alarms. 51 



JEtea anguina — Colour, white; 12, and sometimes 13, 

 tentacles. 



Membranipora pilosa — Light brown colour; 12 tentacles. 



M. pura — Very light brown in colour; 16 tentacles. 



Diplopora cincta — Colour, dark brown; 13 tentacles. 

 Observed the true mouth open and shut, apparently by 

 means of a sphincter muscle, as mouth opened from an in- 

 visible point to a small circular area and then closed again. 

 A very line polyp. 



Lepralia Elleril — Bright scarlet in colour; 24 tentacles; 

 epidermal layer thick; the spines round the mouth protruded 

 through it, and showed clear and colourless. 



Cellepora fusca (?) — 16 tentacles; colour, various, from 

 orange to dark purple and sometimes dark dull green. 

 Under the microscope the pigment cells in that part of the 

 animal which invests the cell are of a red or purple, or some- 

 times intensely black colour ; rarely distinct, generally com- 

 pletely coalescent, and sometimes variegated with beautiful 

 silvery streaks — a most gorgeous sight. 



Retepora cellulosa — Colour, pink and rose red; 12 tentacles. 



Petralia undulata — Colour, brown ; ovicells with scarlet 

 ova. 



Idmonea radians — Colour, delicate French grey; 8 

 tentacles. 



Serialaria Wooclsii and S. Australis — Both 8 tentacles ; 

 basal tubes with granular masses scattered about. 



Aet. XIII. — Electric Fire Alarms, 

 By B. E. Joseph. 



[Bead 8th September, 1881.] 



This paper is brought forward with a view of drawing- 

 attention to the assistance "electric fire alarms" afford to 

 our fire brigade organisation. A system of fire alarms may 

 be described as a means by which information as to the exact 

 locality of a fire breaking out can be transmitted without 

 delay to the fire brigade station. 



