Spelling : a single or double “i” at the end?

This is a question about the nomenclature convention, or, more specifically, the spelling convention.Sometimes I see the italicized spelling Hyriopsis cumingi or Hyriopsis schlegeli, and other times I see the italicized spelling Hyriopsis cumingii or Hyriopsis schlegelii. Which is correct: a single or double "i" at the end?The question goes to the naming/spelling convention. According to the taxonomy experts, single or double "i" ?

I have just received the last issue of Xenophora magazine (AFC publication : http://www.xenophora.org/ .
And guess what is inside ? The explanation of thye ii mystery When some dedicate a species to someone (human) he transforms
the name with "us". Then Two cases appears :

The name does not already finish by a "i"
====> Name = cuvier => Conus Cuvierus
Then "us" bcomes "i"================>Conus Cuvieri

The name does already finish by a "i"
====> Name = cuvieri => Conus Cuvierius
Then "ius" bcomes "ii"================>Conus Cuvierii

I hope my english is not too bad 😉
(Answer by M. Touitou David via the Forum)

Thanks for the information about the single or double i at the end of the species name.
That would mean that any species named for Hugh Cuming, whose last name does not end in an "i", would be spelled "cumingi", correct? And assuming that Hyriopsis schlegeli (italics) was named for a man of German ancestry named Schlegel (sure looks and sounds to me like the German language), whose name does not end in an "i", would be spelled as typed above, correct?

Exactly but the author can latinize cuming as
cunmingus or can decide to latinize cuming as
cumingius… I guess the author latinized with a "ius"
(Answer by M. Touitou David via the Forum)