1880. ] Zoölogy. 445 
of the function of speech. He find it to be very large in the hip- 
popotamus, relatively three times as large as in the horse, while 
it is very much reduced in the seal. On the other hand, in the : 
porpoise it is relatively larger and considerably more convoluted 
than in man. It differs from that of man in being highest behind 
and tapering forwards; in man it is higher in front and tapers 
backwards 
On THE INTERNAL STRUCTURE OF THE BRAIN oF LIMULUS 
POLYPHEMUS.'—Several years ago I attempted to study the brain of 
the horse shoe crab (Limulus polyphemus), and had it sliced into 
a large number of sections. Owing to interruptions these sec- 
tions, made from unstained alcoholic specimens, were not exam- 
ined: during the past winter I have been able with the aid of Mr. 
N. N. Mason, of Providence, to take up the study afresh, Mr. 
Mason has kindly made sections, both transverse and horizontal, 
‘Stained with osmic acid; also sections of the brain of the supra- 
cesophageal ganglion of the lobster, stained with picro-carmine, 
for comparison. The following results, then, are based on over 
two hundred sections of the supra-cesophageal ganglion of Lim- 
ulus, but more especially on one brain, which was cut by Mr, 
Mason into fifty-six sections, from yap to 4y of an inch in thick- 
Similar arterial coat, but this we have failed to find ; the brain is 
Protected by a thick membrane (“ perineurium” of E 
formed of fibrous connective tissue, and the nerves are protect 
Read at the meeting of the National Academy of Sciences, held at Washington, 
April 21, 1880. 
