When scientific names don't make sense!

(from the SERTC inverts taxonomy website)

Every so often, I find myself looking over scientific names in latin-and wonder "What the heck does that mean???"

I have written on this subject on several other occasions:

-a more general treatment here.
-a specific case addressing deep-sea brisingid starfish here.

Understand-sometimes I will have known this name for YEARS without knowing what the actual Latin translates into! And back in the old days, THAT was why the name was given as a Latin descriptor-to make it easy to remember!!!

Thus, I am often perplexed when the names make NO SENSE (or maybe they do but for the wrong reason-bear with me!)

The other day, I happened to be looking up the name of this handsome western Tropical Atlantic beast:
Luidia senegalensis (Luidiidae)

Okay..that makes sense. Luidia, as discussed earlier, is named for Welsh naturalist, Luidius..and so, "senegalensis" ..so basically "from Senegal" which is in Africa? Sounds straightforward, right??

Imagine my surprise-checking the records. This species has been collected from the "American"side of the tropical Atlantic (e.g., Florid,a Jamaica, etc.)..but not from Africa!

Oops! So perhaps, an erroneous collection locality record? YIKES! That name's being sitting around since 1816!! And who described it?? None other then famous French Biologist LAMARCK (and later J. Muller & O. Troschel)!!
Pisaster giganteus (Asteriidae)
So, now what about this one??

Hey! West coast Marine biology naturalist guys! How many of you know what Pisaster ACTUALLY means??
Well...the easy part is "-aster" for star...The first part of that? Is for "pise" for "pea or bean" in reference to all the knobby spines on the surface!

But what about the Latin descriptor giganteus? In one sense, that doesn't seem to surprise anyone..."gigantic" or "big"...but if you've ever worked with one, Pisaster giganteus has NEVER seemed overly large... (the one above is only about a foot across)
That is UNLESS you look at the Holotype! (i.e., the specimen on which the species was described)...its Frakkin' HUGE..

Observe. Curiously, the type is also six rayed. A fact, which fortunately did not make its way into the description!

Hippasteria spp. (Goniasteridae)
Finally....a mystery which I've never quite managed to understand. Some names just DONT' MAKE SENSE.
But here's the thing:

Hippasteria literally means "Horse star" (Hippa for horse and -aster for star). At first, I thought..well, maybe I misunderstood it, so I tracked down the original description from 1840 and lo and behold some of the first species described have names like "Hippasteria equestris" so..."horsy horse star"??

I don't get it. They don't look like horses. They don't have features that look like horses.

STARFISH ARE NOT HORSES. So why name it after one??