neptune —
Neptune-X ISA bridge driver
neptune0 at intio0 addr 0xece000 irq 239
ne0 at neptune? addr 0x300
The Neptune-X is a Ethernet interface card initially designed by Hirofumi
  Shimada, which uses popular NE2000 or its clone with its own x68k-proprietary
  bus to ISA bus bridge.
The NetBSD neptune
    driver takes charge of the ISA bridge part of the Neptune-X. It is
    implemented as a more generic `bus' with its own
    bus_space(9) interface,
    and is intended to be used with
    ne(4) driver.
The neptune device appeared in NetBSD
  1.4.
neptune itself is always detected when it is specified
  in the kernel config file. This is because the Neptune-X ISA bridge is
  transparent to software. The attached device is detected appropriately.