Saurian which can properly be said to be a maritime animal. In the whole of that group of islands, as he tells us, there is only one rill of fresh water that reaches the coast; yet this reptile frequents the sea-beaches, and no other parts of the islands. He adds that it is the only known existing Lizard that feeds exclusively on aquatic productions. Although he refers both species to the genus _Amblyrhynchus_, the aquatic sort now constitutes the genus _Oreocephalus_ of Dr. Gray, and it bears the name of _O. cristatus_. This Lizard, according to Mr. Darwin, "is extremely common on all the islands throughout the archipelago of the Galapagos. It lives exclusively on the rocky sea-beaches, and is never found--at least, I never saw one--even ten yards inshore. It is a hideous-looking creature, of a dirty black colour, stupid and sluggish in its movements. The usual length of a full-grown one is about a yard, but there are some even four feet long. I have seen a large one which weighed twenty pounds. On the island of Albemarle they seem to grow to a greater size than on any other. These Lizards were occasionally seen some hundred yards from the shore swimming about; and Captain Colnett, in his 'Voyage,' says, 'they go out to sea in shoals to fish.' With respect to the object, I believe that he is mistaken; but the fact stated on so good an authority cannot be doubted. When in the water the animal swims with perfect ease and quickness, by a serpentine movement of its body and flattened tail--the legs, during this time, being motionless and closely collapsed on its sides. A seaman on board sank one, with a heavy weight attached to it, thinking thus to kill it directly; but when an hour afterwards he drew up the line, the Lizard was quite active. Their limbs and strong claws are admirably adapted for crawling over the rugged and fissured masses of lava which everywhere there form the coast. In such situations, a group of six or seven of these ugly reptiles may oftentimes be seen on the black rocks, a few feet above the surf, basking in the sun with outstretched legs. I opened the stomachs of several," continues Mr. Darwin, "and in each case found it largely distended with minced sea-weed of that kind which grows in thin foliaceous expansions of a bright green or dull red colour. I do not recollect having observed this sea-weed in any quantity on the tidal rocks; and I have reason to believe that it grows at the bottom of the sea, at some little distance from the coast. If such is the case, the object of these animals occasionally going out to sea is explained. The stomach contained nothing but the sea-weed. Mr. Bynoe, however, found a piece of a Crab in one; but this might have got in accidentally. The intestines were large, as in other herbivorous animals."