'|34 PHILOSOPHICAL TRANSACTIONS. [aNNO 1757. 



d The third or largest pair,-^, e, e, e. Four egg-shaped bodies, which the animal moved when 

 swiming. — f, f, f, f, f, f. The six hinder legs or feet, with which it held a branch of the coralliDe, 

 and was thus enabled to bend itself about in all directions. — g. The tail, at the end of which 

 is the vent, — h. The eyes. — Fig. 24. Another animal found on the same corallines. — a. The ani- 

 mal in a prone situation. — b. Jna supine situation. — c. Considerably magnified. — Fig. 25, 26, il7, 

 28, 29, SO, 31, 32 exhibit certain luminous and other animalcules found in different corallines 

 magnified. — The animalcule c, fig. 32, was of a highly singular appearance, and had a great many 

 limbs. 



XXXIII. Remarks on Dr, Job Easter s Observationes de Corallinis, &c. in tlie 



foregoing Article. By Mr. John Ellis, F. R. S. p. 280. 



Dr. Baster endeavours to prove, that corallines are not of an animal, but a 



vegetable nature; and has brought many arguments to support his system; 



-which to gentlemen not well acquainted with the subject may appear plausible. 



It is to be wished that the Doctor had read and examined thoroughly what has 



been lately written on the subject. 



His first argument is, that because he does not find as many polypes in the 

 corallines adhering to ships, flood-gates, and buoys, as in deep water on oysters, 

 muscles, and rocks, therefore he concludes that corallines are not formed by 

 polypes. In answer to this, let us examine the pliable structure of these bodies, 

 and how wisely nature has defended such tender substances with a tough thin 

 membranaceous covering, and we shall find that the sea is calm enotigh often 

 near the surface to give them leave to grow, even jp. the strongest currents : 

 though doubtless they are more liable to be destroyed in such agitated situations 

 than in the calm depths of the sea. 



His 2d argument is, that finding polypes are not equally dispersed over the 

 whole plant, how can they form it? and gives an example, pi. 5, fig. 13, of a 

 Coralline that is incrusted with many other corallines or polypes on the stem, but 

 has none on the branches. Here we plainly see the mistake : the Doctor looks 

 for the tender part of the polype on the surface of the coralline, considering it as 

 a plant ; and indeed, if this was the case, he ought so to do ; but he never once 

 takes notice of the internal hollow structure of the stem, branches, and denticles 

 of those bodies, to inform us whether he found an animal in those parts or not. 

 This material point he seems not to have thought on ; which is really the true 

 point in controversy at present among gentlemen who have not examined these 

 bodies recent in sea-water. 



His 3d argument is, that almost always one and the same coralline plant 

 cherishes polypes of different kinds; and refers us to fig. 10 and 12. In fig. lo 

 he gives an elegant painting of a geniculated red conferva for a coralline, sur- 

 rounded, as is very common, by many species of small corallines and escharas. 

 And in fig. 12 he gives a drawing of one of the tubular corallines, with the head 



