The head of the _Asterolepis_, like the heads of all the other Cœlacanths, and of all the Dipterians, was covered with osseous plates,—its body with osseous scales; and, as I have already had occasion to mention, it is from the star-like tubercles by which the cerebral plates were fretted that M. Eichwald bestowed on the creature its generic name. Agassiz has even erected species on certain varieties in the pattern of the stars, as exhibited on detached fragments; but I am far from being satisfied that we are to seek in their peculiarities of style the characters by which the several species were distinguished. The stellar form of the tubercle seems to have been its normal or most perfect form as it was also, with certain modifications, that of the tubercle of the _Coccosteus_ and _Pterichthys_; but its development as a complete star was comparatively rare: in most cases the tubercles existed without the rays,—frequently in the insulated pap-like shape, but not rarely confluent, or of an elongated or bent form; and when to these the characteristic rays were added, the stars produced were of a rather eccentric order,—stars somewhat resembling the shadows of stars seen in water. Individual specimens have already been found, on which, if we recognize the form of the tubercle as a specific character, several species might be erected. The accompanying wood-cut (fig. 24) represents, from a Thurso specimen, what seems to be the true normal pattern of these cerebral carvings. Seen in profile (_b_) the tubercles resemble little hillocks, perforated at their base by single lines of thickly-set caves; while seen from above, (_a_,) the narrow piers of bone by which the caves are divided take the form of rays. The reader will scarce fail to recognise in this print the coral _Monticularia_ of Lamarck, or to detect, in at least the profile, the peculiarity which suggested the name. [Illustration: Fig. 25. SCALES OF ASTEROLEPIS. (Nat. size.) a. _Inner surface of scale._ b. _Exterior surface._] [Illustration: Fig. 26. PORTION OF CARVED SURFACE OF SCALE. (Mag. four diameters.)]