The ventricular system is a set of four interconnected cavities (ventricles) in the brain, where the cerebrospinal fluid (CSF) is produced.
 Within each ventricle is a region of choroid plexus, a network of ependymal cells involved in the production of CSF.
 The ventricular system is continuous with the central canal of the spinal cord (from the fourth ventricle) allowing for the flow of CSF to circulate.
 All of the ventricular system and the central canal of the spinal cord are lined with ependyma, a specialised form of epithelium.
Reissner's fiber "(named after Ernst Reissner)" is a fibrous aggregation of secreted molecules extending from the subcommissural organ (SCO) through the ventricular system and central canal to the terminal ventricle, a small ventricle-like structure near the end of the spinal cord.
 In vertebrates, Reissner's fiber is formed by secretions of SCO-spondin from the subcommissural organ into the ventricular cerebrospinal fluid.
 Reissner's fiber is highly conserved, and present in the central canal of all chordates.
 In cephalochordates, Reissner's fiber is produced by the ventral infundibular organ, as opposed to the dorsal SCO.
The Indiana Canal Company was a corporation first established in 1805 for the purpose of building a canal around the Falls of the Ohio on the Indiana side of the Ohio River.
 After several attempts, and possible sabotage by a supporter of the Louisville and Portland Canal, the project was ended.
The Louisville and Portland Canal was a 2 mi canal bypassing the Falls of the Ohio River at Louisville, Kentucky.
 The Falls form the only barrier to navigation between the origin of the Ohio at Pittsburgh and the port of New Orleans on the Gulf of Mexico; circumventing them was long a goal for Pennsylvanian and Cincinnatian merchants.
 The canal opened in 1830 as the private Louisville and Portland Canal Company but was gradually bought out during the 19th century by the federal government, which had invested heavily in its construction, maintenance, and improvement.
 The Louisville and Portland Canal became the McAlpine Locks and Dam in 1962 after extensive modernization.
The central canal, also known as ependymal canal, is the cerebrospinal fluid-filled space that runs longitudinally through the length of the entire spinal cord.
 The central canal is continuous with the ventricular system of the brain.
 The fourth ventricle narrows at a region called the obex to become the central canal of the spinal cord.
 The central canal helps to transport nutrients to the spinal cord as well as protect it by cushioning the impact of a force when the spine is affected
Observatory Inlet is an inlet on the North Coast of British Columbia.
 It is a northward extension of Portland Inlet, other sidewaters of which include the Portland Canal.
 The entrance of Observatory Inlet, from Portland Inlet, lies between Ramsden Point and Nass Point.
 Ramsden Point also marks, to the west, the entrance of Portland Canal.
 Observatory Inlet was named by George Vancouver in 1793, because he set up his observatory on the shore of the inlet, at Salmon Cove, in order to calibrate his chronometers.
 His two vessels, HMS "Discovery" and HMS "Chatham", stayed in Salmon Cove from July 23 to August 17, 1793.
 During this time a boat surveying expedition under Vancouver himself explored Behm Canal.
 Vancouver also named three headlands at the entrance of Observatory Inlet: Maskelyne Point, for Nevil Maskelyne, the Astronomer Royal, Wales Point, for William Wales, the mathematical master who sailed with James Cook, and Ramsden Point, after the famed mathematical instrument-maker Jesse Ramsden.
Storehouse No. 3 is one of four historic storehouses built by the United States Army along the Portland Canal on the west coast of North America.
 Built out of rubble stone in 1896, they were built at a time of tension with neighboring Canada over exact location of the international border in the area.
 The border location was resolved by arbitration in 1903, with two of the four warehouses falling in Canadian territory.
 None of the warehouses were apparently ever used.
 Storehouse No. 3 is located on Halibut Bay, on the northwest side of the Portland Canal.
 The storehouse was listed on the National Register of Historic Places in 1977.
Portland Inlet is an inlet of the Pacific Ocean on the coast of British Columbia, Canada, approximately 55 kilometers north of Prince Rupert, British Columbia.
 It joins the Chatham Sound opposite the Dixon Entrance.
 It is 40 kilometers long and as much as 13 kilometers wide.
 It drains the Portland Canal, Nass River, and Khutzeymateen Inlet, among others, and is the site of Pearse Island and Somerville Island.
 Other than Nass Bay and the Portland Canal, other major sidewaters of the inlet are Observatory Inlet and its east arm, Alice Arm.
The Indiana Central Canal was a canal intended to connect the Wabash and Erie Canal to the Ohio River.
 It was funded by the Mammoth Internal Improvement Act, Indiana's attempt to take part in the canal-building craze, started by the Erie Canal.
 $3.5 million was allocated for the project, the largest piece of the entire $10 million Act.
 However, due to the Panic of 1837, Indiana suffered financial difficulties and had to turn over the canal to the state's creditors, and building of the canal was stopped in 1839.
 The canal was supposed to extend 296 mi , from Peru, Indiana, to Evansville, Indiana, where it would reach the Ohio River.
 It was originally divided into two sections, North and South.
 Later, a third section was designated, called the Indianapolis section.
 Only eight miles were completed, with eighty additional miles between Anderson, Indiana, and Martinsville, Indiana, having been partially built.
The Portland Canal is an arm of Portland Inlet, one of the principal inlets of the British Columbia Coast.
 It is approximately 114 km long.
 The Portland Canal forms part of the border between southeastern Alaska and British Columbia.
 The name of the entire inlet in the Nisga'a language is K'alii Xk'alaan, with /xk/alaan/ meaning "at the back of (someplace)".
 The upper end of the inlet was home to the Tsetsaut ("Jits'aawit" in Nisga'a), who after being decimated by war and disease were taken under the protection of the Laxsgiik (Eagle) chief of the Nisga'a, who holds the inlet's title in native law.

Question: Which was a longer canal, the Indiana Central Canal or the Louisville and Portland Canal?
Answer: The Indiana Central Canal