261 



to which Dana, in 1847, apportioned thirteen genera, appeared, 

 the year after, under tlie auspices of Edwards and Ilairae, with 

 about eighty. Tlie comparison, philosophically conducted, of 

 these two classifications, would be of the highest interest, but I 

 speak of them now only in connection with a new species of 

 Astrajan, recently fallen upon, in arranging the cabinet of this 

 Society. Its discovery furnishes one more proof of the absolute 

 necessity of some laws, plain and sure, by which classification 

 may be determined. A description of the coral will show the 

 difficulties under which a natui'alist must, in such a case, labor. 



AsTR^A DECACTis, Lymau. 



Polyps short and budding from the upper edge ; consequently 

 the corallum takes the form of a thin plate, which, in this case, 

 is somewhat wavy, and has a few swelhngs on its surface. A 

 ground surface shows the corallum, between the calicles, to be 

 solid, with a few very small pits, or vesicles ; this is generally 

 the case, but, where the calicles are a good deal crowded, the 

 intervening corallum is made up of a double row of vesicles. 

 The calicles, when not crowded, are nearly round, but each is 

 surrounded by a fence of grains, which takes the form of a more 

 or less regular hexagon. These grains cannot be seen without a 

 lens ; there are generally about five on a side, (in all about 

 thirty,) and the fence, which they form, is situated midway be- 

 tween each calicle and its neighbors. The calicles are from one 

 half to three quarters of a line in diameter, and are remarkable, 

 not only for their small size, but also from the fact of their hav- 

 ing only te7i stout lamellfe. These laraelh^ are sensibly smooth 

 on their sides and edges, (and the species would thus come under 

 the Sub-Family Eusmilinai of Edwards,) they are considerably 

 exsert, and extend outward a little beyond the edge of the cali- 

 cle ; inwards, they run to a point nearly half-way to the centre, 

 when they pitch suddenly downwards and become thinner ; at 

 the centre they all join a solid columella, which has an oval form, 

 and projects above the level of the lamellae, at their point of 

 juncture with it. On examining a calicle with a strong lens, 

 there may sometimes be seen, on the edge of the calicle and mid- 

 way between the lamellfe, fine points, or grains, whose size does 



