No. 6. — Report on the Dredging Operations off the West Coast of Central America to the Galapagos, to the West Coast of Mexico, and in the Gulf of California, in charge of Alexander Agassiz, carried on hy the U. S. Fish Commission Steamer "Albatross," during 1891, LiEUT. Commander Z. L. Tanner, U. S. ]Sr., Commanding. XXVIII. Description of tivo new Li:^rds of the genus Anolis from Cocas and Malpelo Islands. By Leonhard Stejneger. Tlie two Anoles here described were the only reptiles obtained on the islands of Cocos and Malpelo during the expedition. Each species is peculiar to the island upon which it is found. Of the two, the one from Malpelo seems to be most highly specialized, there being no nearly related species on the mainland with which I am familiar, while the species from Cocos Island belongs to a group which has a number of representatives in Central America. The two species are only distantly interrelated, inasmuch as they belong to widely separated sections of the genus. It is quite possible that a more thorough search on Cocos Island might reveal additional reptiles. In fact, Mr. Townsend informs me that he saw a snake there which escaped. Anolis agassizi,^ sp. nov. Diagnosis. — Tail cylindrical, ■without crest or keel; dorsal scales keeled, subequal to those on the flanks, slightly smaller than the ventrals, and separated from each other by one or more rows of minute granules ; ventral scales keeled ; digital expansions very large ; about thirty-six trans-verse lamellae under ii and iii phalanges of fourth toe ; occipital scale about as large as ear-opening ; scales of supraorbital semicircles very much enlarged (forming high, tuberculated crests in the adults), and separated by one row of small scales; occipital separated from supraorbital semicircles by one or two series of scales ; supraocular scales rough or rugose, sometimes irregularly keeled ; canthus rostralis sharp ; mental shield single, with a deep sulcus posteriorly, very large ; tibia nearly equalling the head in length, and at 1 Named in honor of Professor Alexander Agassiz. VOL. XXXVT. NO. 0.