p. 47-50 ; 24 cm.Includes bibliographical references

Allen, J. A. (Joel Asaph), 1838-1921.

Baur, Georg, 1859-1898.

Salisbury Expedition to the Galapagos Islands (1891)

American Museum of Natural History Scientific Publications

Article IV.-ON A SMALL COLLECTION OF MAM-MALS FROM THE GALAPAGOS ISLANDS, COL-LECTED BY DR. G. BAUR.By J. A. ALLEN.Dr. G. Baur, of Clark University, Worcester, Mass., has kindlyplaced in my hands for identification and description, the smallcollection' of mammals recently obtained by him on the SalisburyExpedition to the Galapagos Islands. The collection numbers12 specimens, representing 4 species. rwo prove to be intro-duced species of Mus, while one is a Bat of the genus Atalapha,and the other a species of Oryzomys, allied to 0. galapagoensis(Waterh.).Atalapha brachyotis, sp. nov.Apparently similar to Atalapha varia (Poeppig) from Chili, but rather smaller,with disproportionately smaller ears, and shorter thumb.General color above reddish chestnut, the hairs plumbeous at base, broadlyringed subapically with yellowish rufous and tipped with chestnut, much darkeron the lower back and tail; below blackish with the tips of the hairs ashy.Ears small, rounded, blackish, as also the lips. Wing and interfemoral mem-branes black, as are also the fingers. Posterior half of the interfemoral mem-brane very thinly haired.Measurements.-Head and body, 47 mm.; tail, 44.5; ear, 7.6; tragus, 4.3;forearm, 39; thumb, 6.4; second finger (matacarpal), 42; third finger (meta-carpal, 43.2, Ist phal., i6, 2d phal., i6.7, 3d phal., 3=) 79; fourth finger, 63;fifth finger, 53 ; tibia, 20; foot, 8.4.Based on a single specimen in alcohol, collected on Chatham Island, June 23,1891.As nearly as can be judged, this insular form closely resemblesA. varia in coloration, size and proportions, except that it hasmuch smaller ears. The hariness of the interfemoral membraneis apparently similar in both, in A. brachyotis there being only afew short hairs beyond the basal half.Compared with A. noveboracensis of North America, atside fromthe striking color differences, A. brachyotis is a much slendererform; while the linear measurements are about the same, the[47]48 Bulletin American Museum of Natural History. [Vol. IV,body is much smaller, and the wing bones much more slender.There is also a marked difference in the dentition, which is verymuch slighter, notably shown in the size of the canines, which inA. brachyotis are only about half as large as in A. noveboracensis.Dr. Baur writes me: "On Chatham Island, at an elevation ofabout 1700 feet, where the hacienda is placed, we observed batsnearly every evening, but were for a long time unable to kill aspecimen; the one I send, the only one collected, was shot byMr. Adams."Bats have been observed on Indefatiguable Island by Dr.Habel, and I observed one on South Albemarle."Mus decumanus Pall.Musjacobia? WATERH, Zool. Voy. Beagle, I, pt. ii, 1840, P. 34.I refer to this species a mummified specimen, " found dead onAlbemarle Island, opposite Crowley Island, Aug. 9, i891." It isan adult, and measures as follows: Head and body, I90 mm.;tail, 203 ; hind foot, 34. Above the general color is yellowishchestnut, profusely mixed with longer wholly black hairs, passinginto yellowish brown on the 'sides; below buffy white at the sur-face, the hairs from near the tips to the base pale sulphery white.This seems to be the form collected by Darwin (op. cit.) onJames Island, where he found it very common, but he does notappear to have actually met with it at any of the other islands.Mus rattus Linn.Represented by one specimen in alcohol, about two-thirdsgrown, apparently not distinguishable from an ordinariy black ratof corresponding age. It was taken on South Albemarle, July29, I89I.I also refer provisionally to this species an imperfect skeletonfound on Duncan Island. This specimen consists of the skulland anterior half of the spinal column, of a full-grown but notaged individual, agreeing in size with Mus rattus.Oryzomys bauri, sp. nov.Evidently allied to Oryzomys galapagoensis (Waterh.), but differing from it inproportions and coloration.Nd. i.] Allen on Mamma/sfrom the Galapagos slands. 49Pelage full and long. General color above dusky grayish brown, faintlyvaried with pale yellowish brown; below the pelage is white at the surface,passing into plumbeous. Muzzle lighter and more grayish, tin'ged stronglywith yellowish brown on the sides of. the muzzle and faintly so on the chin.Ears large, obtusely rounded, almost naked within, well haired externally on theanterior third, and sparsely haired over the rest of the outer surface. Feetabove thinly haired, white faintly tinged with yellowish; soles naked, 6-tuber-culate; posteriorly smooth and pale horn color, anteriorly granulated andyellowish, slightly varied with gray. Tail indistinctly bicolor, nearly naked,the annulations showing distinctly through the very short hairs; above du'skybrown, below ashy brown.Measurements.-Male Adult: Total length, 280 mm. ; head and body, 132;tail, I47 ; hind foot, 32.5 ; fore foot, i8; ear, i8. Female Adult : Totallength, 269; head and body, 124; tail, I45; hind foot, 3I; fore foot, i6.5;ear, I7.3. Younng Male: Total length, 248; head and body, io8; tail, 138;hind foot, i6.5; fore foot, 14.5 ; ear, I6. 5.Skull, 6 ad.: Total length, 37.4; basal length (condyles to incisors), 27.5;greatest zygomatic breadth, i8.3 ; least interobital breadth, 5.6; length ofnasals,'13.5 '; from posterior border of palate to incisors, I4.7; length of lowerjaw (tip of incisors to condyle), 22.8; height at condyle, 9.9.Based on 5 specimens in alcohol, namely, i male adult, I male two-thirdsgrown, I male half grown, I female adult, and i female about half grown,taken on Barrington Island, July 9 and I0, I89I. There are also three invertedskins in antiseptic solution, taken at the same place and time. The adult malemay be considered as the type.This species is apparently nearly allied to 0. galajpagoensis,described by Waterhouse from specimens collected by Darwin onChatham Island, about thirty miles east of Barrington Island.While of about the same size as 0. galapagoensis, it has largerears, and the tail is half an inch or more longer than the headand body instead of being an inch or more shorter, as in 0. gala-pagoensis. In coloration it is evidently much less varied withyellow, as in 0. galapagoensis, the prevailing color on the sidesof the body is described as yellow. In 0. bauri the coloration isabout as in Sigmodon hispidus-the prevailing color being duskygray, with only the slightest mixture of pale yellowish brown.The young are slightly darker than the adults; the female has aslight mixture of pale yellowish-tipped hairs.0. bauri, and doubtless also 0. galapagoensis, is a true Oryzomys,as regards the skull and dentition; it has, however, a much[May, 1892.] 450 Bulletin American Museum of Natural History. [Vol. IV.]thicker, longer, and coarser pelage and larger ears than 0. palus-tris and its near allies.Of this species Dr. Baur writes me as follows "On Barring-ton Island the small Rodent was pretty common; it was foundbetween the bushes near the shore, and also high up betweengrass and the lava rocks."Of 0. galapagoensis Darwin writes (Zool. Voy. Beagle, I, ii, p.66): " This mouse or rat is abundant in Chatham Island, one ofthe Galapagos Archipelago. I could not find it on any otherisland of the group. It frequents the bushes, which sparinglycover the rugged streams of basaltic lava, near the coast, wherethere is no fresh water, and where the land is extremely sterile."The only other species of mammals thus far reported from theGalapagos Islands are two species of Eared Seals, namely, Otariajubata (Forst.) and Aretocephalus australis (Zimm.), specimens ofwhich were obtained in I872 by the Hassler Expedition' (seeAllen, Mon. N. Am. Pinnipeds, i88o, pp. 208 and 21I). The listof known indigenous species thus numbers only five.

Mammals from the Galapagos Islands

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