$51 
on the Coast of Scotland. 
The specimens of Alcyonium digitatum, here procured, 
though all belonging to the same species, differed considerably 
in form and colour. By comparing them with the figures 
which Ellis has given in his Essay on Corallines, p. 83. tab. 
xxxii. a. A. A $. and Phil. Trans, liii. p. 431. tab. xx. 
f. 10-13., no doubt remained in my mind with regard to the 
accuracy of the delineations which he has given, although doubts 
have been expressed by M. Lamouroux on the subject *. This 
naturalist having examined a species of Alcyonium, which he 
has described and figured in bis “ Polypiers Flexibiles,” p. 336. 
tab. 1$. f. 4. a. B. and tab. xiii, under the title A. lobatum, suf- 
fered himself to be misled in a way not uncommon, it is said, 
among his countrymen, by assuming similitude upon too slight 
grounds, and then confounding this similitude with identity. 
Hence he hastily concluded, that the A. digitatum of Ellis and 
the A. exos of Dr Spix (Annales du Museum, xiii. tab. 33.), 
belonged to his species. But the tentacula in his species are 
subcylindrical, rounded at the extremity, and covered above on 
the margin with blunt tubercles ; the tentacula of the A. digi- 
tatum of Ellis are pointed and pinnated, while the tentacula in 
the A. exos of Spix, (the magnified appearance of one is exhi- 
bited, ib. fig. 7.), are subclavate, blunt, and villous. These re- 
markable disagreements of character between the figures of 
Ellis, and those of Spix, did not escape M. Lamouroux ; but he 
accounts for them, (and the same reason we presume, he meant 
should apply to the want of resemblance between their figures 
and his own), by saying, iC Cette difference est due peut-etre a 
Timperfection des instrumens dont se sont servis ces auteurs,” — 
a charge brought, we believe, for the first time against Ellis, whose 
reputation for accuracy it cannot injure ; nor can it be more 
destructive to the credit of the Bavarian naturalist. 
In the course of conversation with the keeper of the light- 
house Mr Reid, a judicious observing man, I was informed that 
rats (the brown or Norway rat, which abounds in the Hebrides), 
after a shower, go down upon the. rocks, while the limpets are 
* In consequence of not employing sufficiently powerful lenses, Ellis and others 
have failed to observe the armature of diverging spiculae at the summit of the 
ridges on the body at the external base of the tentacula. 
