Miscellaneous. 263 
as was formerly supposed, but, besides the spinal cord and brain, 
only the upper sensory nerves. The inferior roots are best seen in 
transverse sections, as Stieda correctly states. The description of 
the nerves given by Stieda would be perfectly correct had he not 
started from the supposition that the nerve-roots lie only in the 
sheaths of the myocommata (ligaments). According to Stieda the 
nerves entering the ligaments would be alternately a sensory and a 
motor one. But only the former enters the ligaments ; the motor 
nerves are interligamental. Behind each ligament originates an 
upper root, which soon enters the ligament and runs towards the 
skin. The fibres are very delicate, and united at their issue from 
the spinal cord into a round cord. There is no dilatation; small 
nuclei lying in the commencement of the cord probably represent 
the spinal ganglion. The motor roots behave differently. The en- 
velope of connective tissue, which closely embraces the spinal cord, 
is furnished along its lower edge, and, indeed, in the entire posterior 
half of each myocomma, with apertures through which fibres of the 
spinal cord, the motor nerves, issue. The fibres proceeding from the 
apertures unite first of all into a flat cord, and then radiate upwards 
and downwards over the inner free edges of the fibrillar lamine. 
Their direction crosses the edges. For each edge a fibre bends 
round in a wide curve, and applies itself thereto under a very acute 
angle. These fibres enter into the fissure between the rectus and 
the longus dorsi. Large specimens, 4 centims. long, present a re- 
markable appearance in the five segments following behind the anus. 
Those fibres which go to the upper half of the part of the myo- 
comma lying below the spinal cord are converted into transversely 
striated muscular fibres from the lamine nearly to the spinal cord. 
I use the term “converted” only for the more easy description of 
the facts. When the spinal cord is isolated by Owsianikow’s 
method, the origins of the motor nerves appear upon it only as slight 
conical elevations. 
The heart commences at the free end of the cecum, runs along 
the upper edge of the latter towards the intestine, and, bending 
round, then passes along the ventral surface of the intestine towards 
the branchiw. The part lying on the cecum is at first a simple 
tube, then a system of from four to five parallel tubes repeatedly 
communicating with one another and possessing cecal diverticula 
on both sides. The part situated by the intestine is again simple. 
Of the branchial rods some, which are rather thicker, are cleft at 
the lower end, the others not. Besides this previously known 
peculiarity, they are distinguished by the form of the transverse 
section and the shape of the canal contained in them. The blood 
passes from the branches of the branchial artery first of all into the 
canal of the cleft rods, and thence through the vessels running along 
(not in the interior of) the transverse rods, into the uncleft rods. 
The canals of the branchial rods open above into branchial veins, 
which, bending backwards and downwards, open into the aortas. 
From the aorta, which is double in the branchial part, although 
simple further back, there originates on each side interligamentally 
an upper branch to the longitudinal muscles, and ligamentally an 
inferior branch, which, running along the ligaments, ramifies upon 
