ECOLOGY AND TAXONOMY OF Halimeda 23 



Fig. 14. Surface utricles of H. incrassata, as observed with an Ellis Aquatic Microscope 

 (Fig. 13) from the collection of the Science Museum, London, using the No. 1 objec- 

 tive. Most of the numerous faint dots or small circles in the utricles are chloroplasts ; 

 the darker spots and curves are associated with subsurface structure. Both may have 

 encouraged Ellis to think of polyps (cf. Fig. 12). The average diameter of the surface 

 utricles is 45-85 \im. (Photograph British Crown Copyright. Science Museum, 

 London.) 



which he sells at 3 Guineas & half; the Wilsons at the same time is 

 fitted for the Solar apparatus so that by having a small box with the 

 Solar apparatus which cost[s] 2 & | Guineas more you have a compleat 

 Microscope for any object. I never could see the smallest animalcules 

 in the Double or Compound microscope. This does very well for the 

 larger objects and is pleasing to many on acct of the largness of the 

 Field. 



Ellis' consideration of corallines as animals was further strengthened 

 by his deductions about their chemistry such as he demonstrated to the 

 Society of Arts, Commerce and others. He showed that corallines, when 

 burned, produced not the "smell of burnt vegetables", but "an offensive 

 smell like that of burnt bones, or hair". Indeed, the door of the room 

 where the Society was meeting "was obliged to be opened, to dissipate 

 the disagreeable scent, and let in fresh air" (Ellis, 1767). 



Such arguments for the animal nature of Halimeda were part of the 

 fascinating and well-reasoned letter Ellis wrote to Linnaeus in 1767. 

 This letter, a portion of which is also a paper in the Philosophical 

 Transactions, was one of two of Ellis' works chosen for citation in the 



