84 



N Arc UAL IlISTOllY OF lilJWS. 



scssor, with his ntnplc wings, long bemling ncrk, and lower inan<liblo, occ:isionally 

 dipjwil into, and j>loughiiig, llio surfaL-e, and the facility with which ho j.roeures his 

 food, cannot but consider it a juere playful amusement, when compared with the dash- 

 ing immersions of the torn, the gull, or the fish-hawk, who, to the superficial observer, 

 api>ear so superiorly accommodated." 



Darwin observed the skimmer in South America. That excellent observer gives 

 us tlic following account of its habits: "Xcar Maldonado (in ]May), on the borders 

 of a lake which had been nearly ilrained, and which iu couscciucnco swarmed with 

 small fiy, I watched many of these birds Hying backwards and forwards for houm 

 together, dose to lis surface. They kept their bills wide open, and with the lower 



mandible half buried in the water. Thus skim- 

 ^^ ming the surface, generally in small flocks, they 



^S— -^^^S^l^ ploughed it iu their coui-se ; the water was quite 



'^^"'"^ -^*lJ^ smooth, and it formed a most curious spectacle to 



behold a flock, each bird leaving its narrow wake 

 on the mirror-like surface. In their flight they 

 often twisted about with extreme rapidity, and 

 so dexterously managed, that they ])Iouglii'd up 

 small fish with their jnojecting lower matnlibles, 

 and secured them with the upper half of their 

 scissor-like bills. This fact I repeatedly witnessed, 

 as, like swallows, they continued to fly l)ack wards 

 and forwards, close before lue. Occasionally, 

 when leaving the surface of the water, their flight 

 was wild, irregular, and r.ajtid ; they then also 

 uttered loud, harsh cries. When these birds were 

 seen fishing, it was obvious that the length of 

 the ])riraary feathere was quite necessary iu order 

 to keej) their wings dry. AVhen thus enipli\vcd, 

 their forms resembled the symbol by which numy 

 artists represent marine birds. The tail is much 

 used in steering tlioir inrgular course." 



It has already been hinted at, on a previous 

 l)age, that the super-family PROCELLAROI- 

 DE.J5 miglit perhaps better constitute a sepa- 

 rate order, Tiil)iiiares. Their differences from 

 all the foregoing birds are many and important, 

 an<l their aflinities seem to be more with the Steganopodes and Herodiones than with 

 the gulls or the auks, to some of which many of the j)etrels show a remarkal)le external 

 and superficial resemblance. We Avill give their essential charactere, as contrasted with 

 those of the Laroidea', in order to show this. The petrels are holorhinal, the gulls 

 schizorhinal ; the former have tubular nostrils, the latter nOrnud ones ; whenever a 

 hind toe is present, it consists in the jietrels, of one phalanx only, while, iu the gulls, 

 the normal number of two j)halanges is always ])rescnl, however rudimentary the toe ; 

 in the jjctrels, the great pectoral muscle is disposed in two quite se])aratc layers, an 

 arrangement unknown in the gulls, and {he j>tctaruli.i tertius of the former is entirely 

 unrepresented in the latter ; the muscular formula of the legs iu petrels is, as a rule, 

 ABXY, a combination, so far as we know, never found in the gulls; the form 



I'Ki. 30. — .SUcluluu ol giuiil luliuar. 



