Yeah your animals are looking good! Really like the last fish. The design on the two dinosaurs facing eachother is clean.
Think the perspective on the pen holder is a bit off actually. Look at the inner upper ring. Its not aligned with the others the right way. You need to make the line over the widest points of the circles face in the same direction, but you probably knew that.
My sketchbook: http://www.conceptart.org/forums/showthread.php?t=78068