Love reckons by itself alone — Love-Shell

The question is to find something never feels the sun and has love in its name. Love-shell lives deep in the sand. Shell has the definition of "an empty or hollow thing; mere externality without substance" (OED 25a), which fits this poem's description.

Some shells have the male and female sexual organs in one body. It's rumored that love-shells will leave their shells at the full moon to increase and find new shells.

Love reckons by itself-alone-
"As large as I"-relate the Sun
To One who never felt it blaze-
Itself is all the like it has-
(F.812/J.826)
[1] Love:: love-shell, Cypraea, a common shell.
[2] relate the Sun:: it thinks the sun is as large as itself.
[3] never felt:: it lives in the sand and never meets the sun.
[4] all the like:: love-shell knows and loves itself only.

Other species of Cypraea, known to the French as Porcelaines, or as Pucilages, and by the English as "Love-shells" are used as ornaments, etc. Children sometimes place them to the ear, to listen, as they say, to the sound of the sea. The small Cypraea are made into clasps, buttons, ear-rings, bracelets, etc. ─ The Utilization of Minute Life (1864)

The inhabitant of this shell, it is said, has the power of quitting it, and of forming a new one better fitted to his necessities, or convenience. "The Cypraea live deeply buried in the sand, from whence it is said, at the full moon, and during its increase, they leave their habitations, for the benefit of conchologists, and crawl forth in a state of nakedness, to expatiate on the rocks above, and to begin a new dwelling." This accounts for the great numbers, and high state of preservation in which these shells are found. Naturalists, however, doubt the ability of these animals to leave their shells. The name of this genus appears to be derived from that of the Cyprian goddess, on account of the great beauty of the species. ─ Outlines of Geology (1836)