Overall your work throughout this lesson has been pretty well done! When it comes to applying the concepts of construction, you've demonstrated a good grasp of how you can combine these different forms to produce solid and believable results. The biggest issue at play for now comes down to the way you decide on which forms to draw, and how they ought to be shaped in specific terms - in other words, more time being invested in the actual observation of your references will yield more accurate results. There are definitely cases where your constructions start to feel more improbable simply because they deviate from what we know to be realistic proportions - something that relies more heavily on ensuring that we look at and study our reference almost constantly, taking only short moments to construct a specific form on the page before returning to the reference image. This is all to avoid working from memory, which tends to simplify and distort the information gleaned from the reference.

That said, there are a few things I can point out in terms of your technique and constructional approach that should also yield some definite growth, though you are already moving in the right direction. Let's break them down into individual categories:

Use of Additional Masses

Looking at examples like your camel's humps, one thing I noticed is that when adding your additional masses, they tend to sit kind of lightly on the structure. Instead, try and make the forms really spill over and "grip" the existing structure, emphasizing how they wrap around it. Bringing it further down also gives us the opportunity to have those masses all integrate with one another, wrapping around the big shoulder/hip masses as well, as shown here.

One thing that helps with this is to think about how the mass would behave when existing first in the void of empty space, on its own. It all comes down to the silhouette of the mass - here, with nothing else to touch it, our mass would exist like a soft ball of meat or clay, made up only of outward curves. A simple circle for a silhouette.

Then, as it presses against an existing structure, the silhouette starts to get more complex. It forms inward curves wherever it makes contact, responding directly to the forms that are present. The silhouette is never random, of course - always changing in response to clear, defined structure. You can see this demonstrated in this diagram.

Head Construction

Looking at how you're approaching constructing your heads, I think you may not have gone through the explanation available here on the informal demos page. This is something I intend to incorporate into the core lesson to really get into how the head construction is made up of different components that all wedge very snugly together, like a puzzle in 3D space, and how the eye sockets are the first, most important step to defining how the rounded cranial ball can be separated into more complex arrangements of planes. For the content I haven't yet been able to formalize into the core lesson material (generally because they're all in-progress things that I develop by explaining things to students in my critiques), I place that stuff under the informal demos page - so make sure you read through them.

Focus particularly on how the eye sockets are shaped. I've found more recently that pentagons with the point down provide us a slot for the muzzle in between, and a flat top for the brow ridge to cross.

Leg Construction

Overall your leg construction is coming along well, although I noticed in a number of these you opted for balls at the joints. This isn't a bad strategy to experiment with by any measure, but I think it's allowing you to leave things a bit oversimplified, rather than actually solving the problem at hand.

You don't appear to be getting into any of the more specific form detail beyond the simple sausage structure. This is something I called out in Lesson 4, when I provided you with [this ant leg demo]() showing just how much more complex we can make things. This comes back down to the issue with observation - establishing the core structure to start is good, but that doesn't mean you're done. Once it's in place, you should be looking back to your reference to identify further structure that can be built up.

For the knobby joints, I would recommend sticking with the sausage method as it's written (without the ball forms in between), and then building up the additional structure around those joints as shown here.

Texture

Just a quick reminder - texture isn't about being as detailed as possible. It's about conveying information. Often times we can achieve this more effectively (and without as much visual noise) by focusing on fewer, but more intentionally designed shadow shapes, rather than a lot of separate lines. So you handled it much better in these birds' feathers (especially the leftmost two), than you did on this bear.

Additionally, this squid was overall really well done, although the suckers on its tentacles should probably have been implied more through the use of shadow shapes to avoid the greater visual noise from having all those lines crammed into a small space. The way you approached the texture on its head was much more effective.

Conclusion

All in all you're definitely moving in the right direction, but I think investing more time into observation to help inform the specific choices you make in construction, and to do so more consistently (avoiding long stretches of drawing without looking back at the reference) to reduce working based on memory, will help strengthen your results further. As such, I'm going to assign a couple additional pages of animal constructions. Be sure to take these as far as you reasonably can (that is, in terms of construction, before you even start worrying about detail/texture).

I recommend that you do these on different days, ensuring that you're able to give everything to each individual drawing. Hell, if you feel you need to spend more than one day on a single drawing, that is fine too. In fact, it's encouraged.