My aliens in my generation ship story are reptilian with some mammal characteristics.
They have 2 hands, each of which has 6 fingers. 2 of those fingers are thumbs and the thumbs are on opposite sides of the hand. This allows them to get a better grip.
Their feet are shaped just like ours but with 6 toes instead of 5.
They have nostrils but no real nose. Their eyes are like cat's eyes. They have 3 antennae at the top of their head for hearing.
Their skin is scaly. I mean sure, human skin close up with the naked eye looks scaly and on a microscope looks like actual scales but my aliens truly do have scales and not just overlapping skin flakes.
Their pregnancy I think is the weirdest of all their weirdness. It starts off like a human pregnancy but with multiple eggs ovulating(10-15 is average). Then the eggs temporarily implant in the womb as the shell develops. Once the shells are fully formed(unlike snake eggs, they don't fuse(the shell is too hard for that)) the alien goes into labor. But this isn't a live birth, it is just the first stage of the pregnancy finishing and second stage starting. After the alien lays eggs, she puts them in her pouch to keep them safe and warm. After a few months of incubation, the eggs hatch and the mother produces milk.
Now I first thought that the chest would be a good place to have the pouch but then my momma told me that maybe I should have it on the abdomen kind of like a kangaroo and that if it was on the chest, these human shaped aliens would lose their balance and possibly break their eggs.
So here are the creatures I used to make these aliens:
Arthropod in general for the antennae
Cat for the eyes
Lizard in general for the nostrils without a nose and the scales
Human for the shape and locomotion
Kangaroo for the pouch
But I am not sure if I should have the pouch on the chest or on the abdomen. On the one hand, a pouch on the abdomen would be safer. On the other hand a pouch on the chest makes more sense to me in terms of distance to milk supply. I mean where else would you expect milk supply on a humanoid creature than the chest?
So where should the pouch go, on the chest closer to the milk supply but at higher risk of breaking eggs or on the abdomen further from the milk supply but safer for the eggs?
I am not sure how to classify these creatures. I mean there is implantation like in placental mammals(except without a placenta and only temporarily as the shells develop). But then there is egg laying like monotremes. And a pouch to incubate the eggs like a marsupial. And scaly skin like reptiles. And milk production like all mammals