COC ae De Ve gO ae’ ' x. ~ abe’ aN he ay at Ph a Nas Nagy aw PD al ad ad egy ccueeceeunry ~~ gu w-~ wlw” ; igi te gg | wy ~ my ie ~~ +o: Po lethcsted tan hl cyt Vrrrwy be wed we me, w@ w ~w~ A = = ~ Lis Wives u Pi wV'pre'y. 2 Nye es ayy é Tl Abide’ le a a A ed Wia'’ge 7 "7 a aS oa, wo ¥ E : eS aa OOD sey oe ‘ tp eh Pd “atl, " ‘ odd Sey aaah aa vowels. vider vs wietureye whet welt weve. we pag ag Yyray Oe eos SSrew os es AR “= ee Fo eee oP RY he day 1 Naty cae vungyl! wae By ryyt>, A he ( 4 ovum 4 Cus Be wee.. ig wu, : vVy Savy y Wwe. wey ! ij Pi Tw s fe Pp ue" The Del abel. Tal Wyre Maay: 5° we Wye. wy Adehitbehdal TWO a tetNai att! Niwatie | veescti Pesta. Meee 2 LETT ; few w y tis elu Se sf J) tM Wen WN aa ty! " "ye, Lge SSS nes tere at tA SIT T*. * pie . . 4 =witp ure” 4 OT leh dtd Leaked Ed By 'y Mey aye i SET Maven hte yVomtteey, WUE Pa nee! | toes 4} Ais angetyt-..--- | Wy awd evs vay yanee Li hah aN | eeveyareteTn vey Tiles eet a EET ey weuvrvevdeytewe tiny TNlyiyy roe ee ee “Seem 2 iver weyiiin. | < hd) |) Lee) eel k Hl gp OPP e eee sre. | Ug ST lyer” < eee gree ReCe gar re wmprecteeucn niemm Te” aaeee ~ ensttnnerennetamernee | aU es SUC esa tbbletefbebeh +4 + ( huskautubalas ew error t etugeeut a en Pt ag Pee Nas key > Vows Cee CE Ue wm . { 7;e ? rae 5 WA tama t oY 4h ' " Wi yituny i ddhibbbialal tae NO wee AP : : arta vier ay F ne E Ssentdey RA hl nach Lh rit yay yUNIUNTE etal ee ray Ad LN wwe aveu wns LAY || D {4 ee eU Nee vam We Pv TNTE NT Ai) Til Midd y 4 ee We, a 4,;,~ / y 44 ~ \ a ~ == Y ‘Ml i 1 ‘ =/-/~™ NWA4 SVL Fa aA re eT ‘ EAA Mb fen tS TA, 701 IAG. aN aN ale AT Is AEX ZE Mo Atty \ i To RV ENN ~ = = 7 5 ¢ ees Fn Ps rey) N — SSN yor ie! an IX, a Ch ay $i} MEY TOP RIAN, NS >7 XS ! ¥ tlh / Me ‘CT wl = SOS “INN p “= ! _ ~ . VA / as, WV (7 mI S 7 | eae a Ara 1M >. US ay A ie “A 70> SPIN = . 1 7 SY SNF \ a et WA sie Ae N/~7 1 F x. WH ache ane ie, Sb RT| 7 4 ~ 1 VAL Da Wid FIRS “ion WA te Be i= VA SE Il Sa O NNER GE teen Near =: Lay io _ 4 —~ ni cay a8 ‘ > Mayr SN) 7S ~\2 XN UREN ey a bed ger et XJ Geological Column Recent Tattlary ey Crefacic TITIASSIC Carhoniferaus Devonic oa Siluric = Ordovicic UZ A : Cc ambric LLLLALEA Carmplex rocks Im a » crystalline & PU! Metamorphic LS Sedimentary Fic. 1.—Generalized geological map and typical cross-sections of the region within a radius of 3800 miles of New York City The oldest rocks of the region are those comprised in the crystalline areas of the Adirondacks, New England, and the Blue Ridge and Piedmont portions of the Older Appalachians. These three areas may be roughly pictured as an oldland enclosing an inland sea or depression on the west where the Cambric, Ordovicic, Siluric, Devonic, and Carboniferous sedimentary deposits were laid down. The Cambric and Ordovicic formations are essentially limestones and shales, not resistant to erosion, cn he for the persistence of the present Great Appalachian Valley along the western flank Ce) e oldiand. After the deposition of the Siluric, Devonic, and Carboniferous beds there occurred the compres- sion of the region which produced a general folding of the sedimentary beds next to the oldland where the Appalachian ridges and valleys appeared. Further west there was no disturbance, the horizontal bedding is preserved and the region is characterized as a plateau. During a later period (the Triassic) certain regions in the original oldland became covered with red sand deposits interbedded with extensive lava flows, and portions of these areas were preserved from later denudation by being downfaulted into the crystallines. They now constitute the Connecti- —eut Valley and the Triassic Lowland. The latest geological formations are those comprising the present coastal plain on the eastern side of the oldland mass. 4 ANNALS NEW YORK ACADEMY OF SCIENCES at the end of each day’s journey, and this indeed is a very essential item in good physiographic work. To facilitate our observations and to aid us in understanding the features of the region under consideration, we have at our command an almost inexhaustible amount of literature. Probably no other region of the world has been studied so intensively and in so truly a scientific way as the area that interests us. The work of many masters, fostered by the institutions of learning concentrated here in the east and developed out of the earlier fundamental studies in geology and physiography, is accessi- ble to every one of us and there is no literature in any branch of knowl- edge so easy of reference and so well catalogued as the geological and physiographic literature of this country. Then there is a practical and even more important reason why we should turn our attention toward these opportunities so near at hand. The war has brought before us a great problem to which we have to adjust ourselves. Travel must be kept at a minimum. ‘The railroads are overburdened with traffic and traveling for pleasure cannot be en- couraged. Moreover, we are all practicing economy in every direction. Since these things are true, would it not be better for us to stay at home altogether? Decidedly not! Our most important duty, if we are unable to take an active part in the furtherance of the war, is to carry along , our tasks in the most efficient and excellent way possible, and it fortu- nately happens in the case of the physiographer that he can combine the means of taking recreation with the improvement of himself in a professional way. At the present time he must do these things without going so very far afield. When I tell you that I propose to keep him within a circle having a radius of 300 miles and centering in New York, I am prepared to defend it on several grounds. If it seems too generous I must argue that this circle just includes within its margin several points of particular interest: Niagara Falls, Norfolk and Cape Henry, the Blue Ridge and Shenandoah Valley, the Adirondacks, the Allegheny Front in western Pennsylvania, and the White Mountains. If it seems too small my argument then is that the traveler must go far beyond its limits to find a region offering any new types of physiography materially different from those thus circumscribed, for he has here a great concentration of physiographic provinces. The New England Upland, with its monad- nock groups and its extension southward in the Manhattan and Reading | prongs, the Adirondack portion of the great Archean massive, parts of the Great Lakes Province, the Allegheny Plateau, the Older Appalachians terminating northward in the Cumberland and Trenton prongs, the Newer Folded Appalachians so exquisitely developed in Pennsylvania, the LOBECK, NEW YORK CITY, A-PHYSIOGRAPHIC CENTER 5 ADIRONDACK PROVINCE —_—- wee { ‘artlora i Eng land Dissected andy a fe ed ee = ave sig ais — rag, hike tOCK. honcogtaed taeph : Monadriac k la Of lake mai Jaciated | group oa o Gi Win FOCKS. Cc. LIVICar range aS Ge ubaied, ae, fae lated” 70 i#? ar? C5). “a 1b Zone edoatdias !Maturey es Sected arid acia ed ‘nountains and peneplane resistar® Cont— eepadess, srraras Subdued moun di SSE Jaciated Sabah apd WESC CT g: £¢ PaO = ed a — 73 [24a eau: waried Teher ae, Ea Zs Keil Fiountalns 17. ure) isstcted, pela; ) ea mountainous relief; CO SC TEXTUKE; ciate Leny Flat eau, A fegtion. Submature rae of ce Ga of a lo strong Seligh. pare f cee Strorn. hef. vaengre 5 gi eau er OF 7 ‘ SEP section Se Cove € cle mountains of, ry a Strong and wear §, A; evern-cresTed Tidges redortinatinig GOVE va t in “Gred? Valley or sotthtasl! side. fae a Val A paps ted peneplane or weak oF & e o RichmMse folde. Strata, ‘y CLASSIC df, Sligh hy on Want tee “2? inéd weak A Yala Fills Fs 6 eth urely cissected ne - yar, Horses resisiart, cht; moeerare rélief, Mature/ Ciacat p a mountains of ge PuSpS s. accordant alti tudes. Seastal HE: Submature/ y, orssected, and S coastal plain. putialy” la 7 er. “ag ore ‘maturely SIE and “glaciated cealtal & srg “Tomlands moraines, lakes’ and /acustrine plains. Fie. 2.—Outline map of northeastern United States showing the limits of the main physiographic provinces Their subdivisions are briefly characterized above 6 ANNALS NEW YORK .ACADEMY OF SCIENCES Coastal Plain, and the Triassic Lowland are points all practically within this area and within a day’s travel of New York. The teacher of physiography in presenting the principles of the subject to a class usually takes it up in a systematic way, dwelling first upon the work of the various destructive forces which carve out the features of the earth as the rivers, glaciers, waves, and wind, and then taking up the great groups of land forms which are conveniently classified accord- ing to their underground structure, the plains being those of simple undisturbed and almost horizontal strata, and mountains those regions of more involved character, distinguished by doming, faulting, folding, complex metamorphic or crystalline rocks, and by volcanic action. — WORK OF DESTRUCTIONAL FORCES Streams.—The work of streams is brought to the understanding of the student by developing in a deductive way the life history of a stream where drainage has been initiated by uplift of a land mass above sea level. The different stages of youth, maturity, and old age are recog- nized as depending upon the degree of adjustment which the stream has acquired. The peculiarities which characterize each stage are noted, the necessary new terms are introduced, and all of these constitute the data of fundamental information which makes up this part of the subject. When the characteristics of a youthful stream are under consideration the instructor calls to witness the rapids, the waterfalls, the narrow rocky gorge of the Bronx River, its pot-holes, its swift current, and its pro- nounced gradient, or he can go further afield and cite the swift brooks of the Highlands, the Deerfield George in the New England Upland of Massachusetts, or the mountain torrents of the Adirondacks. He may cite the Niagara River system bearing the marks of youth in Niagara Falls, the wonderful gorge, the racing current, and the interruption of its course by the presence of lakes Erie and Ontario. The features of maturity are illustrated bythe upper portion of the Bronx River, where it pursues a meandering course upon a limestone lowland. An occasional abandoned meander may even be cited. Other splendid examples are offered by the Wallkill River and its broad valley in New Jersey and New York, and among other streams which have developed wide open courses upon the softer beds of the folded Appa- lachians are the Rondout and Hsopus Creeks. The Mohawk River in part of its course is a mature stream. Some of the very finest references to mature valleys may be drawn from parts of the New England region, notably in eastern New Hampshire and western Maine, where broad LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER Y Wy ' 2} Wir A, Adirondack Mins. vs B, Berkshire Lowland BR, Blue idge C, Connecticut Lowland Ca, Catskill i7Ns. G Green Ni7ns. H, Helderberg Nits. Kt, Kittavinny Men. M Mr. Moradnock MD, Mohawk Delta = | NV Narraganseéest Gasin _———ae S, Shawangank 1708s. Se ey 7M Terminal Moraine =s \ W, White Mins. Fic. 3.—Diagrammatic map of northeastern United States showing the salient relief features 8 ANNALS NEW YORK ACADEMY OF SCIENCES mature valleys have been opened out below the general upland by such streams as the Saco River and the Merrimac and its tributaries. When consideration is given to the final stage of a stream’s history, that of old age, after erosion has reduced the entire drainage basin to an almost flat surface, the instructor is able to place before his class an unparalleled example in the New England peneplane (Fig. 4). The even crest of the Palisades truncating the westward dipping formations, and impressive for this reason, serves as an illustrative example close at home. Throughout New England, the Hudson Highlands, Schooley Mountain, the rest of the Highlands of New Jersey, and Kittatinny Mountain, the even crest lines of the folded ridges of Pennsylvania, and the Blue Ridge of Virginia this same peneplane finds expression and is known variously as the New England, the Schooley, the Kittatinny, and the Cretaceous peneplane. It is true that this peneplane no longer stands Mt. Greylock ey ce ae = ee ae —e ee = iS SF n, es The New Erb Ma Upland a e In western Massachusetis Field sketch Fig. 4.—Sketch of New England peneplane having an elevation of 1,400 feet in western Massachusetts As seen looking west from Mt. Massaemet, near Shelburne Falls. Two or three monadnocks rise above the peneplane, and the Deerfield River has incised itself several hundred feet below that level. at the level to which it had been reduced. The fact that it has been elevated only makes it the more valuable as an object for study. It pro- vides an example when rejuvenation and the matter of several cycles are discussed. The gorge of the Deerfield River (Fig. 4) and many other New England streams cut below the upland level serve to illustrate the essential features of a topography first reduced to old age and then dis- sected as a result of later uplift, but even still finer examples are to be had in the case of the Monongahela River in Pennsylvania with its great swinging meanders incised below the Cretaceous peneplane of the Alle- ghany Plateau, and the really remarkable entrenched meanders of the Potomac River in its course through the folded mountains of Maryland whose crests still preserve that upland level. To carry out still further the idea of repeated uplift with renewed erosional activity in each cycle reference is made to the three cycles so well displayed throughout the folded Appalachian belt (Figs. 15, 16, 17, 19, 20). The old stage result- ing in the Cretaceous peneplane on the summits marks the first cycle, a second and post-mature stage resulting in the Tertiary peneplane LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER ) developed on the broad valley floors represents the second cycle, and finally the post-Tertiary trenching is the work of the present erosion cycle. No better location can be cited for the observation of these ele- ments of the topography than near Hackettstown, New Jersey (Fig. 15), although they exist almost anywhere in the newer Appalachian belt. Even in the gorge of the Hudson River through the Highlands, the Tertiary cycle is preserved by a great bench or terrace especially well developed on the west side of the stream, a feature readily seen by the traveler from the cars of the New York Central, or even better from the boats on the river (Fig. 5). West Point is apparently built upon part of this bench. With rejuvenation resulting from uplift there should be considered the alternative possibility, that of depression, which may or may not impose EEE ae Saag se AS - = DT a ee pad LGA pi ae E | Cref, efacecy 7ertiary__ pene (Field sketches). The Hudson River Highlands Fic. 5.—Sketches in the Hudson Highlands Showing the characteristic expression of the topography as influenced by the Cre- taceous peneplane on the tops of the mountains and the Tertiary peneplane preserved in an intermediate bench standing two to three hundred feet above the river. old age characteristics upon the streams involved. There are no more suitable examples of a drowned coast with embayed river systems to be had than the northeastern shores of the United States. The ragged and bold coast of Maine and eastern New England, Narragansett Bay with its dismembered headwaters, the great fiord of the Hudson River from New York to Albany, the drowned inner lowland of Long Island Sound and New York Bay, Delaware Bay, and, finest and largest of all, the depressed portion of the Susquehanna River system now comprised in Chesapeake Bay and its numerous arms; these and many other smaller examples may all be cited at this time. Then, aside from elevation or depression, there may be certain acci- dents in the life of a stream which cause it to change its behavior in the 10 ANNALS NEW YORK ACADEMY OF SCIENCES matter of deposition or erosion. An overloaded condition and the develop- ment of a flood plain was brought about in many of the New England streams at the end of the glacial period when a greater amount of detritus was provided than the stream could handle. The remnants of these flood plains are now to be seen in the terraces of the Connecticut, the Westfield, Merrimac and other New England streams. The cutting away of alluvial plains to form terraces has been studied here in detail and hardly any topic in physiography is more fascinating than this one. The ’ Hudson River and Delaware River show similar features. In this connection there is the question of deltas built by streams. The teacher of physiography in this region can hardly cite any good deltas formed by streams entering the Atlantic Ocean at the present time, probably because the tides and currents are strong enough to pre- Manhattan prong of | intents aa She My yu? — The Hudson Feiver — al Haverstraw. (Cield skereh) Fic. 6.—View looking down the Hudson River at Haverstraw, New York The east side of the river is bordered by a portion of the New England upland; the west side by the Palisades, which here swing around in a big are. At their base may be seen a portion of the delta built into the estuary of the Hudson in glacial time. vent the accumulation of material, but he can cite several splendid examples built into the estuary of the Hudson River during glacial time, when its waters stood at a higher level than now. Croton Point is the remnant of a delta built by the Croton River; the clays that encourage the brick industry at Haverstraw come from a similar delta (Fig. 6), and finally there is the large delta built by the Mohawk River at the head - of this estuary, whose flat surface is so well seen by one riding over it between Schenectady and Albany. Trenton, N. J., is built upon a similar delta and the very level coastal region at Norfolk, Virginia, is a part of the earlier delta of the Potomac River. Among other topics usually mentioned when the work of streams is under discussion is the subject of stream capture, and citation is always made of the excellent case in the Catskill Mountains where the head- waters of Schoharie Creek have been diverted by the Kaaterskill, so that there may now be pointed out the sharp elbow of capture, the falls and the misfit upper course of the Schoharie, which are so significant. LOBECK, NEW YORK CITY, A PHYSIOGRAPHIO CENTER {4 If the teacher wishes to discuss the effect of Ferrel’s Law upon the flowage of rivers he may cite the tendency of the short streams on the south side of Long Island to cut most strongly against their right hand or Crawford Notch a glactal Trough * ug: — = — A “44 Pa By chee Z¥. es ae ae 8 ees Nee ty OY 2S 7% se SO OSES * Sipe ag nas Ale h ; ! ” “ke ax Tackerman Fraviné a DANG Ing Cirque ’ oe els -—_~— Fic. 7.—Features of local glaciation in the White Mountains western banks. If he wishes to speculate upon the former extent of the coastal plain over southern New England and northern New Jersey he may use the Connecticut, the Housatonic, the Bronx, and even the Hud- 12 ANNALS NEW YORK ACADEMY OF SCIENCES son River as examples of superposed streams now cutting gorges through the harder rocks discovered by them, although their upper courses are broad and open and significantly adjusted to the less resistant formations. Glaciers.—The subject of glaciation naturally falls under two heads, that resulting from local valley glaciers and usually referred to as alpine,. and that resulting from the passage of a continental glacier or ice sheet. Terminal Moraine Long /sland pLMiLe 4 contour interval 20 Fr. 5 cas ; — el en : ve-2 9, Fo it Sy eater Ta ! G7, an CR fea : ay own, ff 4 Va oe » SO ie eee ae =e ee a ee Terminal Moraine, NJ. eo Fic. 8.—Characteristic view and map of portions of the terminal moraine In the White Mountains as well as in the Adirondacks and possibly in the Catskills, too, very good evidences of alpine glaciation exist. The instructor may with confidence refer to the head of Tuckerman Ravine (Fig. 7), Great Gulf and King Ravine as well formed cirques on the slopes of Mount Washington and the Presidential Range (Fig. 25). Hermit Lake is apparently a little tarn. The mere names of some of the other ravines and features are suggestive, as Ravine of the Castles, Ravine LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 13 of the Cascades, and Castellated Ridge. Note, too, how all of these fea- tures are concentrated on the north and east side of the range. Most of these ravines show the characteristic trough-form of glaciated valleys, but the example par excellence in the White Mountains is Crawford Notch (Fig. 7), which for true charm of outline can hardly be equaled even in the well known glaciated mountains. In the Adirondack Mountains Lake George lies on the floor of a glaciated trough of superb beauty (Fig. 23) and several of the finger lakes of western New York occupy similar valleys of rounded profile. In developing the subject of continental glaciation the teacher refers to the terminal moraine (Fig. 8) with its characteristic knob and kettle | idl , | es ae ee p27 ge hek / Glacial erratic on Long Island Fic. 9.—The largest erratic on Long Island and one of the largest in the eastern United States It is a mass of crystalline rock carried in the ice sheet from New England over Long Island Sound hgeee so easy of access on Staten Island, its continuation across the “Narrows” into Prospect Park, Brooklyn, its bifurcation further east where two terminal moraines form the backbone of Long Island and its fish-lke tail at its eastern end, and then on into Block Island, Nantucket, and Marthas Vineyard. Westward in New Jersey it may be seen in rather classic perfection at Plainfield and at Hackettstown. The lobate form of the ice front is shown by the festoon-like trend of the moraine in New Jersey (Fig. 29) and in Marthas Vineyard. Then there is the great outwash plain fringing the southern side of Long Island and the islands to the east: The city of Plainfield, New Jersey, stands upon such a plain, whence it derives its name. The contrast between glaciated and non-glaciated areas, the difference in soil, the disturbed drainage, the rapids and waterfalls and numerous lakes in one case, their 14 ANNALS NEW YORK ACADEMY OF SCIENCES © absence in the other, the effect of these things upon the activities of the people—all of these topics are readily illustrated in our immediate area. In Bronx Park glacial strie, réches moutonnées, and erratics are under our feet at every step. The “Rocking Stone Restaurant” takes its name _ from a near-by erratic (Fig. 9). The drumlins of the Boston Bay region and the great swarm of western New York (Fig. 10), the eskers of south- ern Maine and an occasional one in New J ersey, the sand plains of New England, the kame hills scattered over New York and New J ersey, are topics of interest. There is also the subject of marginal lakes illustrated by Lake Passaic in New Jersey, Lake Bascom in the Berkshire region, _ and Lake Iroquois in New York. Their outlet channels may still be pointed out, that of Lake Passaic at Moggy Hollow and of Lake Iroquois at Rome, New York, and a later marginal channel at Covey Gulf on the northern flank of the Adirondacks. Fig. 10.—Characteristic view and map of glacial drumlins In strong contrast with all of this there are the normal and undisturbed erosion features of the southern half of our district, where lakes are prac- tically absent and where the soil is all of the residual type. Boulder-cov- ered fields in southern Pennsylvania, Maryland, and Virginia are not known. The aspect of the country is different and this difference is re- flected in the industries and economic development of the region. Waves.—The subject of wave work is no less limited in the prolificacy of examples available. The development of the features upon an emerged shoreline is illustrated in the unrivaled offshore bars and lagoons of the Long Island and New Jersey coast, both typically in the youthful stage, though it may be held that in northern New Jersey where the bar has been pushed back against the mainland maturity is reached. Abandoned shorelines and beach ridges exposed as a result of emer- gence are beautifully displayed in western New York in the old basin of Lake Ontario and it is upon these ridges that the so-called ridge roads have been built. Shorelines of submergence in a region of strong relief are shown in LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 15 the early stages of youth along the coast of New England where wave work has had but little effect, and the outline of the shore is extremely irregular. The New Jersey codst also comes under this class as well as under that of emergence, but the region is one of low relief and is made up of non-resistant formations more readily influenced by wave action, so that bars have been built across the. estuaries and a smooth, sinuous outline has been attained, representing a further advance in the youthful stage over that of New England. The activity of waves in cutting cliffs, destroying islands, tying islands to each other or to the mainland by throwing up sand bars, the building of cobblestone beaches and other features, finds splendid illustrations in Sand Dunes Cape Henry Fic. 11.—Giant sand dwnes on Cape Henry, Virginia, encroaching upon an evergreen forest which borders the coast the eroded drumlins of the Boston Bay region and the tombolos of Nan- tasket, Nahant, and other beaches. The shore of Lake Ontario likewise exhibits the work of waves in cutting away drumlins. The construction of spits by currents where waves are cutting against headlands may be studied in the greatest detail in the compound recurved spits of Cape Cod and Sandy Hook, or the simple recurved spit of Cape Henry, or the suc- cessive offsetting spits of Fire Island, Oak Island, Jones Beach, Long Beach, Rockaway, and Coney Island. Wind.—On all of our beaches the work of the wind in the building of dunes is to be seen. Most noteworthy are the giant dunes of Cape Cod and the great dunes of Cape Henry, now encroaching upon a forest (Fig. 11). The barrier beaches of Long Island and New Jersey are everywhere covered with dunes rising ten to twenty feet above sea level. 16 ANNALS NEW YORK ACADEMY OF SCIENCES CONSTRUCTIONAL FORMS Plains and Plateaus.—Study of the constructional group of land forms is introduced by consideration of plains and plateaus characterized by a simple and almost horizontal structure. The subject begins most natu- rally with coastal plains. The well defined elements of the recent coastal plain of the Atlantic coast, comprising its oldland in southern New Eng- land, New York, northern New Jersey, and the Piedmont further south; its inner lowland partly drowned in Long Island Sound, Lower New York and Sandy Hook Bays, then followed by the main transportation routes between New York and Philadelphia, occupied by the Delaware River from Trenton to the Bay, and thence southward; the features of the fall line seen in the rapids at Trenton, N. J., the falls of the Schuyl- kill at Philadelphia, the Great Falls of the Potomac at Washington, and those of the James River at Richmond; the main cuesta forming the Cuesta, Southern New Versey < er G ASA = AGS = eee Fee FC eS Se SRS Sac SAT Sao I'rG. 12.—Profile view of the coastal plain cuesta, near Clementon, New Jersey It is 15 miles east of Philadelphia and a few miles south of Camp Dix, which is built upon the flat back slope of the cuesta. The soil here is loose and unconsolidated, is very sandy and dry, and supports an open forest of pines and rhododendrons. foundation of Long Island, the Atlantic Highlands at Sandy Hook, its ragged front making up the hilly belt of southern New Jersey, its flat surface the pine barrens which incidentally provide a suitable location for Camp Dix, whose site is near the cuesta front, are all features which may be pointed out in much greater detail than here indicated (Fig. 12). The various genetic types of streams—consequent, subsequent, obsequent, resequent, and insequent—can be illustrated by examples almost too numerous to mention. In central New York the ancient coastal plain provides even bolder features and somewhat greater variety. Its oldland in Canada and the Adirondacks, its inner lowland in Mohawk Valley and the basin of Lake Ontario, its cuestas in the Helderberg Mountains and the Allegheny and Niagara escarpments and many other details could be cited (Fig. 13). Stages in the development of a plain or plateau are illustrated by the very youthful drainage systems of the coastal regions of Maryland and Virginia, by the deeper but still youthful dissection of the Allegheny Plateau, by the headwaters of the Susquehanna River in New York, and LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER a by the mature dissection of the Catskill Mountains and of the western Pennsylvania Plateau region where extreme ruggedness prevails. The economic dependency of people upon the features of a dissected coastal plain, the contrast between the different belts, the routes of travel, the position of towns, the controlling influence of the fall line, the loca- tion of towns, railroads, and roads upon the surface of a youthful plain, but in the valleys of a maturely dissected one, the occurrence of the ex- tensive bituminous coal beds in the Allegheny Plateau region, the advan- tageous methods of mining there compared with those in the folded Ontario CLAY Rochester re) = N, ae Ww. = e ; = - ie CUESTA Fic. 13.—The cuestas and lowlands of western New York anthracite region, these are only some of the topics that may be taken up here with profit. Block Mountains.—The subject of block mountains offers opportunity to mention some isolated examples like Snake Mountain in Vermont near Lake Champlain and others in that general region. A related topic is fault-line scarps illustrated by the really excellent example bounding the New Jersey Highlands on the east and extending northward into New York State, and again the abrupt margins of the Connecticut Lowland separating it from the upland on either side (Fig. 18). Downfaulted grabens or more truly basins resulting from the erosion of downdropped less resistant rocks are represented by the Boston and Narragansett Basins, the long Connecticut River lowland, and the Pomperaug or Southbury Valley in western Connecticut. Rectangular drainage systems 18 ANNALS NEW YORK ACADEMY OF SCIENCES along lines of faulting give strong character to a map of the Adirondacks. Tectonic valleys characterize the New York City region where the Man- hattan Street depression, the Dyckman Street cross valley (Fig. 14), — the Harlem River, and some of the notches of the Palisades owe their position to ancient lines of dislocation. At Saratoga the mineral springs are believed to follow similar lines of displacement. The offsetting and overlapping of ridges resulting from faulting, planation, and later dis- section of a region of dipping alternating resistant and non-resistant beds is illustrated in the Hanging Hills of Meriden and other trap ridges of Connecticut (Fig. 18). ) ml _& WER SES Ty 4 DHEA " WIVES DG SN SSERSFES GLOSS \ y, wy) ° Ie ip ~ EIA IESIRANNN EISSN Cay A ae : Y y 4 / } y x ; YISSIGENY a ae SS NP RSIS SU REZ ES: SSIS = e salient features of northern New York City Geol Column Falisade Trap Triassic ss. Manhatlan Se, /pwood As. Ordham gn. 7h Fig. 14.—Diagrammatic representation of the essential relief features of northern New York City, with cross-sections showing the underground structure The resistent character of the Fordham gneiss, the Manhattan schist, and the Pali- sade trap is noteworthy, as is also the development of the valleys upon the limestone belts. The letters on the diagram refer to the following features: B, Bronx River; BP, Bronx Park; D, Dyckman street cross valley; F, Fordham Heights; FG, Fort George Heights; F W, Fort Washington Heights; FL, Fort Lee; H, Highbridge; Ha, Harlem River ; Hud, Hudson River; P, Palisades; W, Washington Bridge. Folded Mountains.—When the presentation of folded mountains is introduced the teacher may be proud that he can cite examples from this region unexcelled in the entire world. Around Kingston and Catskill the study may be taken up in miniature, but with all the essentials of form. The Little Catskill Mountains make it possible for one in a half day’s journey to see an anticlinal, synclinal, and monoclinal mountain and an anticlinal, synclinal, and monoclinal valley, all in close juxtapo- sition to each other. The Shawangunk Mountains and Rondout hills are within easy reach. In western New Jersey Kittatinny Mountain may be LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 19 studied at Delaware Water Gap (Fig. 17). At Harrisburg, Pennsylva- nia (Fig. 19), the zig-zag ridges developed on pitching anticlines and synclines are of classic renown, and throughout central Pennsylvania the folded Appalachians provide examples of infinite variety and perfection. This whole belt in Pennsylvania, Maryland, and Virginia is so replete with material for the study of folded mountains that it hardly seems feasible to draw any further examples in particular from it. That por- tion forming the Wyoming syncline or the anthracite coal basin (Tig. 27) might receive especial mention as well as two or three other coal The salient features of the Hacker’ stown region. Fic. 15.—Diagrammatic representation of the essential relief features of the Hackettstown, New Jersey, region The infolded, or down-dropped, belts of limestone and shale determine the position of such valleys as that of the Musconetcong River (M) and German Valley next to the east, while the resistent Archean crystallines still preserve the Cretaceous peneplane on the New Jersey Highlands. H indicates the position of Hackettstown, just outside of but within actual view of the terminal moraine. The geological column in descending order is as follows: Martinsburg shale, Jacksonburg limestone, Kittatinny limestone, Hardyston quartzite, Byram gneiss, all of which may be recognized in the cross-section by their symbols and relationship to each other. basins of the east when attention is given to the economic side of the ques- tion. This topic would touch also upon the extent of the Great Valley from Lake Champlain along the Hudson River, through Kittatinny Val- ley, Lebanon Valley, Cumberland Valley, and Shenandoah Valley south- ward. It would also take up the location of towns and railroads in the longitudinal valleys, the character of the soil and related matters. Complex Mountains.—Complex mountains carved out of a foundation of crystalline, metamorphic or highly contorted strata find excellent ex- amples in the Adirondack Mountains, the White Mountains, the Green 20 ANNALS NEW YORK ACADEMY OF SCIENCES Mountains, and in fact all of New England, which is only the stump of a worn-down complex mountain mass extending southward in the New Jersey Highlands (Figs. 1, 2,3). New York City (Fig. 14) is a part of this area. In Pennsylvania, Maryland, and Virginia we find this same type of crystalline rock appearing again in the Piedmont (Fig. 26) and the Blue Ridge portion of the older Appalachians. Crefaceous penerlane 5 ee v * Behe, . fue 4 ae : ange ~ 4 Pm aS ei é Soe" RR Sa as . ale tots he Ba ane hts Tt Pohat cong Er . snenle ae lertiar “Peneplane . é — . a ~ = ~ = : See — oS A Bf a OE Se ee ee te, ee Sains = Silene Gm PS cities Pa ea 8 Yepianes nie ae eet " Steer, te Mi VIST = TEFTia gi% TEN ERING ee Mi co AB a Lele a dye, \ mel 7 SY 4} wy, LR ; “Ss . ' ' \ ¥ wt woh ys \y, Se? a n Se eal wane vee 4 ©) UNM AY Sia OUI U Ot Ma \, Spt NOSSE OV Se ¥en Musconetcong Valley near Hackettstown Fic. 16.—The Cretaceous and Tertiary levels as seen looking west from the base of Schooley Mountain, south of Hackettstown, New Jersey The Delaware Water Gayo reglior . Fie. 17.—Diagrammatic representation of the main relief features in the Delaware Water Gap region The Cretaceous peneplane is preserved on the hard resistant Shawangunk conglom- erate, which forms Kittatinny Mountain, and on the pre-Cambric crystallines which form the New Jersey Highlands to the east. The Tertiary peneplane on the floors of the valleys and the post-Tertiary stream dissection are distinctly indicated. Volcanic Mountains.—Topographic features resulting from volcanic activity in our neighborhood are limited mainly to the trap ridges of Connecticut (Fig. 18), and the Triassic belt of New Jersey (Fig. 29), Pennsylvania, and Virginia, where the Palisades, the Watchung Moun- tains, and Cemetery Ridge at Gettysburg provide examples worthy of , mention. In New England the roots of old volcanoes like Ascutney LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 21 Mountain in Vermont may be cited, although their present form is due entirely to later erosion. In Lebanon County, Pennsylvania, Bunker Hill appears to be an old volcanic neck. | FIELD TRIPS Thus far our efforts have been given to illustrating the principles of the subject of physiography. When the teacher conducts a class into the field or when he undertakes a little more strenuous work there on his own account he will find that all these examples which he has been citing are not grouped there in that nice and orderly way according to topics or following the arrangement of the text book. If he would profit to the greatest extent from what can be seen in the field the investigator ie: 73 The sahent topographic. feat et salen thet VOR er deen Wegion Fic. 18.—Diagrammatic representation of the essential relief features of the southern Connecticut Valley The New England upland preserving the Cretaceous peneplane upon its resistant crystalline rocks and the down-dropped series of Triassic strata with their interbedded trap sheets forming parallel and more or less offsetting ridges as a result of faulting, and also the divergent course of the Connecticut River across a portion of the upland, are all clearly indicated. must be prepared not only to observe and study whatever features present themselves, disregarding entirely the lack of order in which he finds them, but he must also understand the relation which the different steps in the history of the region bear to each other, so that he may grasp and keep in mind, in some sort of coherent and logical order, all of the feat- ures before him. In other words, he must knit together the different threads of knowledge which he has heretofore been spinning independently of each other into a fabric of complex pattern whose design will be mani- fest only when seen in its entirety. ANNALS NEW YORK ACADEMY OF SCIENCES ‘Sydvisodo} oy} JO Sjudttiela }taI[¥s at} a1k UOT}IaSSIP Aretp1ap-js0od oy} puke 100g AvT[VA pvoaq oy} uo pedojeasp sv suvjdoued ArvyWA07, 04} ‘s}sa1d OSpLI oy} UO s}uURUUIAa. OULTdoued SNOVDdR}IA,) ML yo WWSnoaq A[Suo01js ov ‘solrvjpnqi1} JuondDssqus oy} pur ‘saspld VY} Ssoddv AVAIY BUULYeNbDsNg oy} Jo ssanod dsa1eASULA} eL “PoeaAlOAuUl O1B SIOQWOU SUIWIOJ-aspli IMOJ 10 991g} YORAM ur ‘aulpoudAS pouanzAVAO ATYSTIS puv SulyqojId pavAysvoyqj}0U B OJ ONp A[TaewtAd sie Aaq woibats BaingsiAww A ay2? Jo sainqnal Jayas 1Mywassa ay, Jo Won UaSaida. dIQ~DWWYDLODIG—6T “DIA y a = a Sea ge % Hf pashiy Wn V4ouup2ungr YS ah AY YD pg corer eri | 5 yee OMOLSAP// LL. ~, ——— \ ONOIOC, LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 23 The teacher of physiography placed in New York with a knowledge of the principles of the subject but not having a speaking acquaintance with the regional physiography of this area would proceed to enlighten himself in this respect in some such manner as follows: He would ar- range a series of excursions which might be classified, according to the length of time necessary, as half-day excursions, full-day excursions, week-end trips consuming one day and one night, two days and one night, two days and two nights, three days and two nights, and finally more extended trips of a week or so, and perhaps a vacation jaunt over the whole district. Suppose we outline a few of these and suggest briefly the main points of interest in each case, as well as the literature which he would look over before going into the field, and the maps and notes which he would take with him. Second Mtn, Cove Min. (gett ihe 8 etait ee koa.) ae 20 a a ti Se : Lape asS SS SS Eee a ee ey RG if ee ni Vege eae ad ee ee ae bd Marys yi a Si Boy ¢ |! er Es pao S Be.’ | a My Bir Blue _ $ eh ae Art Bate ii aea) Susguehanna River —=™ Mtn. FIG. 20.—View upstream from the summit of Blue Mountain at the Susquehanna Water Gap Showing the even-crested ridges and the broad valley floors with their intrenched streams HauFr-Day TRIPS Staten Island.—The first half-day of freedom would find our explorer on his way to Staten Island armed with a topographic and geologic map of the region and perhaps somes notes gleaned from a perusal of Folios 83 and 157 of the Geological Survey. He probably has looked over Hollick’s (182) paper on Staten Island drift. The contrast between glaciated and non-glaciated areas, the difference in soil, pre-glacial ero- sion, the terminal moraine, its knob and kettle topography, the character of the drift and source of the material are some of the topics which would engage his attention. Palisades.—A second opportunity for a half-day’s trip will result in a study of the Palisades (Fig. 14), going by way of Fort Lee and returning by way of the Dyckman Street Ferry. As usual, topographic and geologic maps should be taken. Folio 83 and the New Jersey State Geological 24 ANNALS NEW YORK ACADEMY OF SCIENCES Map both provide structural cross-sections of the region. Essays by Davis (136, 137, 138) on the geographical development of northern New Jersey and on the dates of origin of topographic forms on the Atlantic Coast, and reports by Kiimmel (141, 142) of the New Jersey State Sur- vey, as well as other New Jersey (254, 256) reports on the physical feat- ures of the State, should be looked over. Consideration on this trip would be given to the formation of vertical cliffs in resistant formations, the Cretaceous peneplane, the origin of the Hudson River, the alluvial ter- races, notches produced by cross-faulting, and also to the matter of glaciation. . . Inwood and Bronx Park.—A third half-day trip will include a study of the Dyckman lowlands (Fig. 14), the anticlinal limestone valley through which Broadway runs, between the Fort Washington and Fort Second Mtn. Blue Min, Susquehanna Wafer Gap Fig. 21.—The great stone arch bridge of the Pennsylvania, Railroad at the Susquehanna Water Gap The piers of the bridge are built upon the same hard formation which makes up the Blue Mountain. Owing to its resistance, this rock occasionally outcrops in the river and forms a series of rifts or rapids, which is true also of most of the other ridge-form- ing strata. George Heights, tranverse faulting in the New York City region, the youthful gorge of the Bronx River with its pot-holes, the mature upper portion, small subsequent valleys in the Manhattan schist, glacial strie, and erratics of Palisade trap. Folio 83 should be studied and articles by Hobbs (45, 46, 47) on faulting and by Kemp (49) on the Bronx River should be kept in mind. OnzE-Day TRIPS Watchung Ridges.—A profitable one-day’s excursion will be a study of the Watchung Ridges at Plainfield, N. J. (Fig. 29). The necessary topographic maps, the Passaic Folio, and the New Jersey Geological Map should be on hand. Articles of reference will include essays by Davis (136, 137, 138) on northern New Jersey; also articles by Lewis (148), - Kiimmel (141, 142), Salisbury (144), and Darton (134). The day’s study is devoted to a consideration of trap ridges, water and wind gaps, LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER warping or faulting of the beds, the stream development of this area, the question of streams superposed from an extensive coastal plain and the Passaic Lake Basin. The terminal moraine is visited near by and note is made of the outwash plain upon which Plainfield stands. Hackettstown. — Another day’s trip takes the student to Hackettstown (Figs. 15, 29). From the car window he observes many of the fea- tures already seen—the trap ridges, the terminal moraine, and the Passaic Lake Basin ; in the field he stands upon the Schooley peneplane at Schooley Mountain, he notes the Tertiary base level and post-Tertiary trenching in Musconetcong Valley (Fig. 16), he understands the ori- gin of the valley structurally, he visits the terminal mo- raine, and sees evidence of earlier drift farther down the valley. Topographic maps, the New Jersey geo- logical map and one or two State reports should be con- sulted as well as the essays already referred to. Long Island. — A third day’s trip takes one out to the Hempstead Bay region of Long Island where gla- ciation is the main topic. Two terminal moraines, out- wash plains, erratics, and ‘SuUIv]UNOy AUeYySa[[y WOIsseidx9 oq} voUeYM ‘MOl[aq Ad[[VA IY} WOIJ SUTe}JUNOM JO JoVdSe OY} JI SOAS NvoyRId vy} JO }UOAJ pjoq neoaiv[q AuUsySaTy 94} JO vdVJAINS oY} 0} SAOI[VA UVIYOR[Vddy 94} MOAZ pvoALeYy vIuBA[ASUUV 94} JO 9JNOAI VY SuUIMOYS A][LIUIBpP LUT ou uoibas Duo0zV ay. fo saungnal Jayas 2D12UdSSa aYZ LO UOIZD2UASANd—aL IUDWWUWDAODIG— ZG “DIT (os f a a ae : Eingeyt DUOOL/y. 1a | U0lB21 BUOOL/Y AY, fo sarybas WNYVOLO Odes LUal/OS AY aS Be WY FAYLND JFCHSISHYOH 20 SUPIYIDIDAAy P2PYOY 26 ANNALS NEW YORK ACADEMY OF SCIENCES alternating beds of stratified drift and till are to be seen. Minor features, such as a mid-bay bar, provide a little variety. The chief papers of in- terest on this trip are Fuller’s Professional Paper on Long Island (175), which contains a splex aid map of the areal geology, and Veatch’s Profes- sional Paper (197) on the water resources of Long Island, which contains useful cross-sections. Long Branch.—Another trip for a day is the one by boat to Long Branch, giving opportunity to see a part of the cuesta of the coastal plain in Atlantic Highlands, and the drowned inner lowland of New York Bay, the great Sandy Hook spit, and other coastal features, including the little wave-cut cliff on the mainland. Besides having the topographic and geologic map the student should have read Davis’ (173) analysis of the development of Cape Cod and referred to Johnson (183) on shorelines. Delaware Water Gap.—A day may be devoted to a study of the Dela- ware Water Gap (Fig. 17), and in this connection the recent topographic sheet of this region published by the Geological Survey, with a physi- ographic description, illustrations and diagrams printed on the back, is most useful. The two peneplanes and the post-Tertiary trenching—in short, the complete history of the Appalachian folds—should be taken up. The articles of Willis (124, 125), Davis (119), and Chamberlin (116) are invaluable in understanding the Appalachian folds. Finally, the vicinity of Paterson offers attractions for another day’s trip. ( QOnr-Day AND OnzE-NicHt TRIPS Shawangunk Mountains.—The question of week-end trips may now receive our attention. By leaving New York late Saturday afternoon the student is still able to reach the field of operations the same night, be ready for an early start the next day and return home late that evening. For example, he may go to Newplatz, either via the West Shore to Highland or the New York Central to Poughkeepsie, then by ferry to Highland, continuing his journey by electric car. The next day’s walk over the Shawangunk Mountains and down to Rosendale, where he takes the train for Kingston, gives him a chance to see the open Wallkill Valley, the rock terraces along its sides representing the Tertiary level, the folded Shawangunk Mountains, delightful in their picturesqueness; the great cliffs of conglomerate, erratics scattered over the plain, glacial striz on the summits, and some of the smaller folded hills, where a splendid cross-section is provided by the gorge of the Rondout at Rosendale. At a distance he may look over the Hamilton plateau whose abrupt eastern edge is analogous to the Allegheny Front further south, and he may also LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER oY obtain glimpses of the Catskill Mountains. He may conjecture regard- ing the position of the Cretaceous peneplane in this area. Besides the topographic map, and possibly the State geologic map which he carries with him, the literature to which he refers will include the New York State Bulletin on the geological history of New York (252), and in this he will be careful to note Darton’s interesting stereogram drawing of the Shawangunk Mountains, and he will also take note of Tarr’s Physical Geography of New York. Catskill—Another profitable trip of this size is the one to Catskill. By leaving New York on the night boat a party may find itself at Cat- skill next morning ready for the field. During the day they are able to u\ 7 Ri u/s The Glacial Trough ,2 of Lake George Fic. 23.—Vista down the open trough of Lake George The islands on the lake floor are frequently characterized by stoss and lee slopes, indicating a southward movement of the ice tongue study the folded hills of the Little Catskills, where every conceivable type of Appalachian mountain and valley is presented. Davis’ (118) articles with sectional block diagrams unravel the whole secret for us. Meriden.—A third trip would set one down in the evening at Meriden, Connecticut, amidst a wealth of interesting features (Fig. 18). The Connecticut Lowland, the faulted trap ridges, forming the Hanging Hills of Meriden, the New England upland, the sharp departure of the Con- necticut River from the lowland into its gorge at Middletown may be seen at first hand, and thought should be given to the physical history of this part of New England. Topographic and geologic maps are essen- tial and reference should have been made to Davis’ splendid survey Mt Monadnock = ee rE outbern New Hampshire. (Field sketch) IEeer = ne oe ee + ta Sas New foswich Hills Geos Vie. 24.—-A typical portion of the well developed New Hngland peneplane with isolated monadnocks in southern New Hampshire ANNALS NEW YORK ACADEMY OF SCIENCES reports (24, 28), his papers and to some of the articles by Hobbs (44) upon the rivers of the region. The Connecticut State bulletin by Rice (259) on the geology of the State and Barrell’s (258) bulletin, entitled Central Connecticut in the Geological Past, are almost indispensable. Two-Days AND OnE-Nicut TRIPs If two entire days and the intervening night may be spent in the field, perhaps the most advantageous results of all may be obtained, especially in the matter of economy. Combina- tions of several of the one-day trips are thus possible. Hackettstown.—For instance, the Hackettstown and Dela- ware Water Gap excursions may be made on successive days by spending the intervening night at Hackettstown or even at the Water Gap. | Beacon Mountain.—Another trip of the same length may be outlined as follows: Leave on the Hudson River day boat, arriving at Fishkill about noon. Go upon Beacon Mountain in the afternoon, continue to Poughkeepsie, cross over to Newplatz, where the night is spent. The next day walk over Shawangunk Mountains to Rosendale, and proceed to New - York by train via Kingston. The first day makes possible the observation of the entire length of the Palisades, the Croton delta, the Haverstraw delta (Fig. 6), the gorge of the Hudson with the remnants of the Tertiary level (Fig. 5), the three erosion cycles represented in the region, and in gen- eral the salient topographic features of southern New York. The Shawangunk Mountain excursion has already been dis- cussed.. For this trip, in addition to the litertaure men- tioned, the student should look over Berkey’s (250) aqueduct report and the papers by Davis. Possibly the New York State Poughkeepsie Bulletin would be useful. Two-Days AND T'wo-Nicuts TRIPS Catskills —By spending two days and two nights on the journey the circle of operations is still further widened. For instance, the party may leave by night boat for Cats- kill, spend the next day studying the Little Catskill folded mountains, stay over that night in Catskill village, and leave the next morning for the Catskill Mountains by way of the LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 29 inclined railway, arriving in New York the same night. To the topics previously mentioned there is added the opportunity to study a splendid case of stream capture as well as to see the big features of the maturely dissected Catskill plateau, and to have an inspiring view over the adja- cent lower country. The additional literature would include a paper by Darton (79) on stream capture and several articles by Rich (90, 91), who has devoted considerable attention to the Catskill region, as well as to papers by Heilprin (86) and Guyot (85). Harrisburg and Altoona.—Again, by leaving New York late in the afternoon the student may reach Harrisburg that evening, and the next morning go by trolley toward Marysville (Fig. 19). He may then walk through the water gap of the Susquehanna River and see some of the great pitching folds of the Appalachians, continuing by train to Tyrone or Altoona for the night. The next morning he may go upon the Alle- Fart of Presidential Range Mt Washington from Mt hearsarge of the North o eteae oe (Field sketch) é eae AN) ee ~Biyehw Law SEE sit Py We i par fe WN : ; yy ae Pf fs Oy AN if dackerrnan Fav Fic. 25.—The cirques on the east side of Mt. Washington in the White Mountains gheny Front (Fig. 22) and possibly spend the day walking back along the railroad around Horseshoe Curve, returning to New York that eve- ning. Such a trip gives a good cross-sectional view of the Appalachian folds whose historical development, comprising the three cycles of erosion, is worthy of careful study. Davis’ (119) paper on the rivers of Pennsyl- vania should in spite of its close reading and strenuous logic have been carefully studied. The very valuable monograph and annual report by Willis (124, 125) upon the mechanism of Appalachian structure, papers by Chamberlin (116) and Campbell (78), and the very easily understood articles by Tower (98) on topography and travel in Pennsylvania, as well as one by Brigham (115), all contribute to an understanding of the region, and finally there is that little manual of Lesley (120) which, although published in 1856, is still highly suggestive. THREE-Days AND T'wo-Niaguts TRIPS Lake George.—Other slightly longer week-end trips may be made to consume three days and two nights, three days and three nights, or even three days and four nights. 30 ANNALS NEW YORK ACADEMY OF SCIENCES One of the popular three-days and two-nights trips is that taken each year in the Columbia University summer field work. The party leaves New York by day boat in the morning for Fishkill, visits Beacon Moun- tain that afternoon, proceeds by train to Saratoga, where the first night is spent. The next day it proceeds to Lake George and by boat as far as Silver Bay, returning to Albany for the night. An early train the next morning takes the party to Catskill for a study of the Little Mountains, and New York is reached that evening. This trip always averages less than $25 in cost, covering everything, and provides opportunity at least to see most of the physiographic provinces of the east. In addition to points of interest already noted for other trips, this one introduces the LIEDMONT UPLAND.” COASTAL PLAIN -_4> 4~4~< LOT FNS pe ee CT a ag SOL aN REN APR EWNG RES FINN NS SAS7 NOE 7 s ey RAINE ROSNER — The Salient features of the Blue Ridge region. Fic. 26.—Diagrammatic representation of the essential relief features of the Blue Ridge and Piedmont region Part of the folded Appalachian ridges are visible at the extreme left. The Great Falls of the Potomac River are worthy of notice because of their physiographic signifi- eance. Mohawk delta, the terraces of the Hudson, and the beautiful glacial trough of Lake George (Fig. 23). Several papers by Kemp (70, 71), as well as by other authors, deserve note. Boston Bay.—A splendid week-end adventure is a trip to Boston Bay and Cape Cod. The night boat puts one in Boston next morning ready for a day at Nahant or Nantasket Beach. The following two days may be devoted to a study of Cape Cod. In this connection Johnson (48) on Nantasket Beach and Davis (173) on Cape Cod may be cited. The stu- dent would do well also to be acquainted with the writings of Shaler (56), Emerson and Perry (34) on Narragansett Basin and Shaler’s (195) survey report on Cape Cod. The New England peneplane, Blue Hill monadnock, the Boston Basin, drumlins, complex tombolos, beach _— LOBHLCK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 3] ridges, wave work, a great compound recurved spit, and sand dunes pro- vide much of interest. ONE TO Two WrEEKsS TRIP New England.—A somewhat more extended trip may be taken which will give a good grasp of all of New England physiography. Leaving New York in the morning the traveler proceeds to North Adams, Massa- chusetts, in the Berkshire lowland. A day may be spent climbing Mount Greylock, and possibly another one walking over that portion of the New England upland pierced by the Hoosac tunnel (Fig. 4). Study of the gorge of the Deerfield River, its terraces and those of the Connecticut and other streams is then conveniently taken up, after which Mount Monadnock forms a good objective (Fig. 24). The chmb up this peak is a very feasible one, although near-by accommodations for the traveler are almost lacking. From there procedure is made to the White Moun- tains by way of Lake Winnepesaukee. If this trip is undertaken before the last part of June it is likely that the railway to the top of Mount Washington will not be in operation, but the walk up by trail from Craw- ford House is very practicable. From the Tip-top House, which now has accommodations for overnight visitors, a carriage road leads down to the Glen House, which is a reasonable and convenient place to stop. The next day a really strenuous climb will take the hardy individual over the northern summits of the range down to Gorham, where he can catch a train for Portland that afternoon. The trip from Portland to New York may be interrupted at Boston for a study of the drumlin region and Cape Cod. If the arm of the cape is rounded by train the explorer will find himself within easy reach of Nantucket and Marthas Vineyard, after which a day’s stop at Meriden, Connecticut, will round out a very com- prehensive journey. This trip embraces almost every topic in New Eng- land physiography, the peneplane and its monadnocks, the longitudinal valleys forming the Berkshire and Connecticut lowlands, the fascinating topic of river terraces, the White Mountain monadnock group, with its glacial features, its cirques and troughs, the drumlins and the work of the waves upon them, the Cape Cod spit, the lobate terminal moraine of Marthas Vineyard and the mainland, and finally the faulted trap ridges of Connecticut. The available literature is rather extensive and would include the contributions of Davis, Shaler, Goldthwait, Johnson, Hobbs, Emerson, Jefferson, Dale, Gulliver, Woodworth, and others. This trip is one which would occupy between one and two weeks and would cost probably between $50 and $75. ANNALS NEW YORK ACADEMY OF SCIENCES fPOCONS PLATEAU Scranion Coal Basin. The salient features oF the Fie. 27.—Diagrammatic representation of the principal relief elements of the Wyoming, or northern, anthracite coal basin This is the largest of the anthracite coal Owing to its synclinal structure the coal-bearing formations were here preserved from erosion. areas of eastern Pennsylvania. ton; W, S, Scranton; P, Pitts- The letters refer to the following cities: All are more or less similar in structure. Nanticoke. Wilkes-Barre; N, Several other trips of similar length to different points of the compass might now be outlined, but it seems more advis- able to combine them in one big swing around the circle, which will. bring the traveler at occasional intervals within easy reach of New York. OnE-MontH TRIP Entire Area. — The journey may start by boat and have as its first objective the city of Nor- folk, Virginia. From this point electric trains make easy a visit to Virginia Beach and the giant dunes of Cape Henry (Fig. 11). The Norfolk Folio of the ‘Geological Survey and minor arti- cles, such as those by Hitcheock (180), should be studied in this connec- tion. The old delta of the Potomac River, the shifting dunes, and the drowned coast offer the main topics of interest. If time and funds permit a short side trip may be made to the Dismal Swamp, which is de- scribed in Shaler’s (187, 190, 193) survey reports. After Norfolk, the jour- ney may be directed to LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 33 Washington, either by boat or train via Richmond. The drowned Chesapeake Bay is to be seen if the first alternative is adopted, and some of the folios of this region should have been glanced over. The in- vestigations of Darton, Shaler, Willis, Fontaine, Clark, Miller, Hunter, and especially McGee (184, 185), throw light upon this region. In case the Richmond route is taken opportunity is given to see some of the isolated Triassic occurrences of the south and to note the location of the Fall Line. Darton’s Richmond bulletin (172) may be useful as well as Surface’s (160) account of the physiography of Virginia. At Washing- ton a visit should be made by electric car to the Great Falls of the Potomac, and realization should be had of the high and low terraces of the Potomac River. The necessary data may be found in the Washing- ton Folio. From Washington a splendid electric line runs sixty miles over the rolling Piedmont country to Bluemont at Snicker’s Gap on the Blue Ridge (Fig. 26). During this ride other occurrences of the Triassic are to be seen. From this point the traveler should walk over the ridge into Shenandoah Valley to take the train for Luray. The important literature covering western Virginia physiography and related topics is in the form of a report by Keith (154) on the Catoctin belt, Bascom (150) on the Piedmont, Geiger and Keith (153, 163) on Harpers Ferry, and Surface’s (160) article already mentioned. An account of the Luray Caverns appears in the National Geographic Magazine (127). The next lap of the journey is by train to Cumberland, Maryland. The entrenched meanders of the Potomac River below the even crest of the folded Appa- lachians are followed by the railroad. The structural relations of the various ridges may be learned from the Papaw-Hancock Folio of the U. 8. Geological Survey. Additional valuable material may be found in Clark and Mathew’s Maryland Survey report on the physical features of the State (265), and articles by Clark, Martin, and Campbell. Between Cum- berland and Altoona the traveler rides in the broad longitudinal valley at the foot of the Allegheny Front (Fig. 22). After a visit to the crest of the plateau he may continue east to Philadelphia, stopping at Harris- burg on the way. ‘Topics and literature pertaining to this important section have been mentioned. A day around Philadelphia gives occasion to see the falls of the Schuylkill, now artificially modified, and the ter- races marking a former shoreline on the oldland in Fairmont Park. A trip out to Chester Valley is well worth while. The main elements of Philadelphia physiography are outlined in the Philadelphia Folio. If the traveler does not now feel obliged to come on to New York he may take train for Wilkes-Barre and Scranton and on the way enjoy a ride on the very crest of some of the Appalachian ridges in the Pottsville coal 34 ANNALS NEW YORK ACADEMY OF SCIENCES region. The environs of Scranton are not likely to be attractive to the visitor unless he is buoyed up with an enthusiasm for the study of the features (Fig. 27). It takes almost half a day to go by train and to walk the necessary distance from Archbald, a few miles north of the city, in order to visit the largest pot-hole in the country, which oddly enough is to be found almost at the top of one of the ridges and was presumably ground out by a subglacial torrent (262). The northward continuation of this journey is highly delightful. Stops may be made at Ithaca and at Watkins Glen. The finger lakes of western New York are studied and some attention is given to the preglacial pattern of the area. Grabau’s studies on this phase of the subject are invaluable. Articles by Campbell (78), Hubbard (88), Tarr (93, 94, 95, 96, 97), Fairchild (82), and Dryer (81) regarding the finger lakes region are very readable. Several folios, The salient Top cgi Features Of the Niagara Falls region L.Ontario Fic. 28.—Diagrammatic representation of the main relief features at Niagara Falls The seven-mile gorge cut during the retreat of the falls from their earlier position at Lewiston is the most striking element in the landscape. The two resistent limestones serving as cuesta formers are indicated in the section. especially the Watkins Glen-Catatonk one, should be noted. Niagara ' Falls is the next important stopping place, and because of its physi- ographic significance should be studied with great care (Fig. 28). The excellent Niagara Falls Folio ought, if possible, to be on hand. Impor- tant papers are those by Gilbert (217, 220), Upham (229, 230), Cole- man (208, 209, 210), Taylor (228), Spencer (225, 227), Wilson (231), Leverett (222), and Grabau’s (251) guide of the region. Of course there is a trip through the gorge to Lewiston. Not far east of Niagara Falls are the ridge roads, built on the old beach ridges of Lake Iroquois. Between Buffalo and Albany the drumlin area should be visited and the physi- ographer should see the old glacial channel at Rome, N. Y., as well as other similar features of interest. The significance of the Mohawk Valley lowland should be thoroughly appreciated. From Albany the traveler may easily return to New York or if he can devote eight or ten days more he can go on to Lake George, Lake Champlain, Ausable Chasm, the LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 35 Green Mountains, the White Mountains, Portland, Boston and then home. Most of the topics of this last portion have already received attention. One of the most important papers to which the student should have refer- ence on this long journey, as well as on many of the smaller ones, is the paper by Fenneman (6) on the physiographic provinces of the United States. It includes an excellent map and summary description. The total length of time necessary for this swing around the circle, | whose radius is within 300 miles of New York, need not be more than thirty days and ought easily to be accomplished for less than $150. In educational value it would outweigh the total of many college courses and would prove a continual source of inspiration to the teacher of physi- ography in the eastern United States. FIELD PREPARATION May I conclude now with a word regarding the preliminary prepara- tion of the student before going into the field. To really be alert in appreciating what he sees and to make the most efficient expenditure of his time and money, the student should put himself to quite a little trouble if necessary to look over before each field trip all the literature that is available. Not only should he look it over and glean from it the essence which seems to pertain to the work in hand, but he should prepare in a compact and easily carried form a digest of the articles he reads. A small note book which will nicely go into the pocket may, by the use of fine though legible handwriting, be made to contain summaries of a great many bulky articles. In case diagrams and maps would be helpful in the field and copies are not available for this purpose, they may be traced off directly in ink upon tracing paper, more or less roughly, and these pasted with the notes they illustrate. The form in which maps are taken into the field has a great deal to do with the use which is made of them. If they are taken along all rolled up the way they come from the publisher, they do not invite fre- quent reference and a listless attitude of mind is likely to result in the user. But if the maps are conveniently mounted on cloth so as to fold up in pocket size their utility is many times enhanced. This applies not only to topographic sheets but to State geologic maps which may be cut into several pieces and each piece mounted in sections so as to fold. The particular style in which one travels depends upon the character of the individual, upon the length of the trip, upon the nature of the region visited, as well as upon the object of the work. As a general thing, when the undertaking smacks a little of exploration and adven- 36 ANNALS NEW YORK ACADEMY OF SCIENCES ture, as it does frequently when the exact route to be followed cannot be predetermined, or when train schedules are not known, or when the walk- ing ability of the explorer cannot be reduced to mathematical exactitude, or when hotel accommodations of towns have not been ascertained, or when all the features to be seen have not been evaluated correctly, then it becomes necessary to travel practically without a detailed schedule, stopping at night wherever one happens to be. This precludes the carry- ing of much impedimenta. A knapsack, which will hold a few note books, maps, some extra underclothing, handkerchiefs, sweater, thin rain coat, and a pair of tennis shoes, can be readily carried all the time, and will not be actually intolerable for ten days or so at a stretch. In fact, this manner of traveling gives a certain delightful sense of freedom not to be had in any other way. ACKNOWLEDGMENTS The bulk of this paper was first given essentially as it now stands in an address before the Physiographers’ Club of New York. It was intended primarily to embody in a compact form a mass of suggestions for teach- ers, and it now appears in a more permanent character through the courtesy of the New York Academy of Sciences. Owing to its condensed arrangement it has been impossible to treat the various field trips in the detail which might seem desirable and many points of interest are neces- sarily quite ignored. It can therefore hardly be classed as a handbook, though it may serve imperfectly as a guide. The subject of physiography has proved to be of high intrinsic value in the present war, and it is no mere braggadocio to say that the man who has been trained in physiography and geology has developed certain qualifications essential to the officer in the field, the ability to use and read maps, the sense of direction, the habit of being out of doors and “on your own,” the knack of making rough sketches and simple maps and especially that “sense of terrain,’ which comes only from work in the open, map in hand. The desire to encourage such studies has been the prime reason for preparing this paper. The importance to the physiographer of using and being familiar with maps of all kinds can hardly be overexaggerated, and it is only because they are so essential and should be used in the original that more of them have not been introduced into this article. For the use of maps and photographs, credit is due as follows: Fig. 1, Geological Map, generalized from U. 8. G. 8., geological map of North America accompanying Profes. Pap. 71;. Fig. 2, Map of Physiographic LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 47 Provinces after Fenneman, slightly modified, descriptions of provinces after Fenneman and Johnson; Fig. 8, Map of terminal moraine from Islip, N. Y., sheet; Fig. 10, Map of drumlins from Clyde, N. Y., sheet, sketch after Tarr; Fig. 13, Cuestas and lowlands of western New York, after map in Niagara Folio; Fig. 21, Susquehanna Water Gap, from Nat. Geog. Mag.; Fig. 23, Lake George, after Detroit Photo. Co. During the preparation of the diagrams the informal criticisms of Mr. F. K. Morris, of the Department of Geology, Columbia University, were distinctly helpful. BIBLIOGRAPHY The references below are grouped according to physiographic provinces. Those preceded by a star are deemed most important from the physi- ographic viewpoint. In the text the numbers following the names of authors refer to this list. The chief journals and periodicals to which reference may be made are: American Journal of Science, American Museum.Journal, Annals of the Association of American Geographers, Annals of the New York Academy of Sciences, Appalachia, Bulletin of the Geological Society of America, Geographical Review (formerly Bulletin of the American Geo- graphical Society), Journal of Geography, Journal of Geology, National Geographic Magazine, and Science. The standard text-books on geology and physiography contain much information upon the features of the northeastern United States. The most convenient bibliographies are those provided in the follow- ing bulletins of the U. 8S. Geological Survey, which are indexed by both subject and author: 44 (1886), 75 (1887-1889), 91 (1890), 99 (1891), 127 (1732-1891), 130 (1892-1893), 135 (1894), 146 (1895), 149 (1896), 156 (1897), 162 (1898), 172 (1899), 188 and 189 (1892-1900), 203 (1901), 221 (1902), 240 (1903), 271 (1904), 301 (1901-1905), 372 (1906-1907), 409 (1908), 444 (1909), 495 (1910), 524 (1911), 545 (1912), 584 (1913), 617 (1914), 645 (1915), 665 (1916). I.— GENERAL x . Bowman, I. 1911. Forest physiography. . Brigham, A. P. 1903. Geographic influences in American history. . Davis, W. M. 1898. Physical geography. . Emerson, F. V. 1908. Geographic interpretation of New York city. Bull. Am. Geog. Soc., XL, p. 587. . Fenneman, N. M. 1914. Physiographic boundaries in the U. 8S. Ann. Assn. Am. Geog., IV, p. 84. He OO Ol 38 #6. *i1G. ANNALS NEW YORK ACADEMY OF SCIENCES Fenneman, N. M. 1916. Physiographic divisions of the U. 8S. Ann. Assn. Am. Geog., VI, p. 19 (with map). . Gratacap, L. P. Geology of the city of New York. . Powell, J. W. 1895. Physiographic regions of the U. S. Nat. Caw Soc. Monographs, p. 65. . Salisbury, R. D., and Atwood, W. W. 1908. Interpretation of topo- graphic maps. Profes. Pap. U. S. G. S., No. 60. . Semple, E. C. 1903. American history and its geographic conditions. . Tarr, R. S. 1902. Physical geography of New York state. . Tarr, R. S., and Martin, L. 1917. College physiography. . Tower, W. S. 1905. Geography of American cities. Bull. Am. Geog. Soe:, XXXVII, p. 577 . Van Hise, C. R., and Leith, C. K. 1909. Pre-cambrian geology of North America. Bull. U. S. G. S8., No. 360. . Willis, B. 1912. Index to stratigraphy of North America. Profes. Pap. U.S. G. S., No. 71 (with geol. map). II.—NEW ENGLAND PROVINCE Barrell, J. Central Connecticut in geologic past. Bull. Conn. Geol. Surv., No. 23. . Barrell, J. 1913. Terraces of northern Appalachians. Bull. Geol. Soc. Am., XXIV, p. 688. . Clapp, F. G. 1908. Glacial period in New England. Bull. Geol. Soc. Am., XVIII, p. 505. 9. Dale, T. N. 1892. Rensselaer grit plateau in New York. 13th Ann. Rept. Ue SG 8S.) Part:2, p. 291. . Dale, T. N. 1898. Slate belt of New York and Vermont. 19th Ann. Rept. U.'S.. G..S:,: Part 3, p. 153. . Dale, T- N. 1905. Taconic physiography. Bull. U. S. G. S., No. 272 . Daly, R. A. 1903. Ascutney mountain, Vermont. Bull. U. S. G. S., No.. 209. 23. Darton, N. H. 1894. Geologic relations from Green Pond, N. J., to Skun- nemunk Mtn., N. Y. Bull. Geol. Soc. Am., V, p. 367. . Davis, W. M. 1888. Triassic of Connecticut valley. 7th Ann. Rept.. U.S, Gs S.,) ps 4ao. . Davis, W. M. 1890. Glacial sand plains. Bull. Geol. Soc. Am., I, p. 195. . Davis, W. M. 1891. Dates of origin of topographic forms on A slope. Bull. Geol. Soc. Am., I], p. 545. . Davis, W. M. 1895. Physical geography of southern New England. Nat. Geog. Soc. Monographs, p. 269. . Davis, W. M. 1897.: Triassic of Connecticut. 18th Ann. Rept. U. S.. G. 'S., Part 25pad . Davis, W. M. 1902. River terraces in New England. Bull. Mus. Comp.. Zool., XX XVIII, p. 281 (also in essays). . Davis, W. M. 1909. Geographical essays. 31. Emerson, B. K. 1891. Triassic of Massachusetts. Bull. Geol. Soc. Am.,. II, p. 451. . Emerson, B. K. 1898. Old Hampshire county, Mass. Monog. U. 8S. G. S:, No, 29. LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 39 . Emerson, B. K. 1899. Geol. of eastern Berkshire county, Mass. Bull. Ue S.*G. S. No. 159. . Emerson, B. K., and Perry, J. H. 1907. Crystalline rocks of Rhode Island. Bull. U. 8. G. 8., No. 311. . Fairchild, H. L. 1914. Pleistocene marine submergence of Connecticut and Hudson valleys. Bull. Geol. Soc. Am., XXV, p. 219. . Fettke, C. R. 1914. Manhattan schist of southeastern New York state. Ann. N. Y. Acad. Sci., XXIII, p. 193. . Fuller, M. L. 1899. Elements in sand-plain formation. Jour. Geol., VII, p. 452. . Fuller, M. L. 1901. Pre-Wisconsin till in southeastern Mass. Jour. Geol., IX, p. 311. . Goldthwait, J. W. 1914. Remnants of an old graded upland on the Presidential Range of White mountains. Am. Jour. Sci., XX XVII, p. 451. . Gulliver, F. P. 1893. Newtonville sand plain. Jour. Geol., I, p. 803. . Hitchcock, C. H. 1896. Geol. of New Hampshire. Jour. Geol., IV, p. 44. . Hobbs, W. H. 1893. Housatonic valley. Jour. Geol., I, p. 780. . Hobbs, W. H. 1900. Pomperaug valley. 21st Ann. Rept. U. S. G. S., Earby, De ba . Hobbs, W. H. 1901. River system of Connecticut. Jour. Geol., cee D 469. . Hobbs, W. H. 1904. Lineaments of Atlantic border region. Bull. Geol. Soc. Am., XV, p. 483. . Hobbs, W. H. 1905. Rock floor of greater New York. Bull. U. S. G. S., No. 270. . Hobbs, W. H. 1905. Origin of channels surrounding Manhattan island. Bull. Geol. Soc. Am., XVI, p. 151. . Johnson, D. W., and Reed, W. G. 1910. Form of Nantasket beach. Jour. Geol., XVIII, p. 162. . Kemp, J. F. 1896. Glacial or post-glacial diversion of the Bronx river. Trans. N. Y. Acad. Sci., Dee. 15, 1896, p. 18. . Kemp, J. F. 1913. Buried river channels of the northeastern states. Proc. Wyom. Hist. and Gaol. Soc., XIV. . Kitimmel, H. B. 1893. Rivers of Connecticut. Jour. Geol., I, p. 371. . Lobeck, A. K. 1917. New England peneplane in White mountains. Geog. Rev., III, p. 53. . Perry, J. H. 1904. Geol. of Monadnock mountain. Jour. Geol., XII, p. 1. . Pumpelly, R., Wolff, J. E., and Dale, T. N. 1894. Green mountains in Massachusetts. Monog. U. S. G. S., No. 23. . Rice, W. N., and Gregory, H. E. Manual of geology of Connecticut. Bull. Conn. Geol. Sury., No. 6. . Shaler, N. S., Woodworth, J. B., and Foerste, A. F. 1899. Narragansett basin. Monog. U. S. G. S., No. 38. . Stone, G. H. 1893. Osar gravels in Maine. Jour. Geol., I, p. 246. . Stone, G. H. 1899. Glacial gravels of Maine. Monog. U. 8. G. 8., No. 34. . Wolff, J. E., and Brooks, A. H. 1897. Age of Franklin white limestone of Sussex, N. J. 18th Ann. Rept. U. S. G. S., Part 2, p. 425. . Woodworth, J. B. 1894. Typical eskers of New England. Proc. Boston Soc. Nat. Hist., XX VI, p. 197. 40 ANNALS NEW YORK ACADEMY OF SCIENCES 61. Woodworth, J. B., and Marbut, C. F. 1896. Queen’s river moraine in Rhode Island. Jour. Geol., IV, p. 691. *62. Holyoke Folio, U. S. G. S., No. 50. *63. New York Folio, U. S. G. S., No. 83. *64, Passaic Folio, U. S. G. S., No. 157. 65. Franklin Furnace Folio, U. 8. G. 8., No. 161. *66. Raritan Folio, U.S. G. S., No. 191. IITI.—ADIRONDACK PROVINCE *67. Alling, H. L. 1917. Glacial lakes of central Adirondacks. Bull. Geol. Soc. Am., XXVII, p. 645. *68. Brigham, A. P. 1898. Note on trellised drainage in Adirondacks. Am. Geol., X XI, p. 219. 69. Cushing, H. P. 1907. Asymmetric differentiation in bathylith of Adiron- dack syenite. Bull. Geol. Soc. Am., XVIII, p. 477. *70. Kemp, J. F. 1897. Physiography of eastern Adirondacks. Bull. Geol. Soc. Am., VIII, p. 408. *71. Kemp, J. F. 1906. Physiography of Adirondacks. Pop. Sci. Mo., March, 1906. 72. Miller, W. J. 1910. Trough faulting in southern Adirondacks. Science, XXXII, p. 95. 73. Miller, W. J. 1911. Preglacial course of upper Hudson river. Bull. Geol. Soc. Am., XXII, p. 177. (See also several New York state bulletins. ) IV.—ALLEGHENY PLATEAU PROVINCE *74, Brigham, A. P. 1893. Finger lakes of New York. Bull. Am. Geog. Soc., XXIV, p. 23. 75. Brigham, A. P. 1897. Glacial flood deposits in Chanango valley. Bull. Geol. Soc. Am., VIII, p. 17. *76. Brigham, A. P. 1898. Topography of Mohawk valley. Bull. Geol. Soc. Am., IX, p. 183. 77. Butts, C. 1906. Devonian section near Altoona. Jour. Geol., XIV, p. 618. *78. Campbell, M. R. 1903. Geog. development of northern Penn. and south- ern N. Y. Bull. Geol. Soc. Am., XIV, p. 277. *79. Darton, N. H. 1896. Stream-rebbing in the Catskills. Bull. Geol. Soe. Am., VII, p. 505. *80. Davis, W. M. 1891. Dates of origin of topographic forms on Atlantic slope. Bull. Geol. Soc. Am., IT, p. 545. *81. Dryer, C. R. 1904. Finger lake region of western New York. Bull. Geol. Soc. Am., XV, p. 449. *82. Fairchild, H. L. 1895. Glacial lakes Of western New York. Bull. Geol. Soc. Am., VI, p. 353. 83. Fairchild, i. L. 1905. Ice erosion a fallacy. Bull. Geol. Soc. Am., XVI, Dp. 15, 84. Foshay, P. M., and Hice, R.R. 1891. Glacial grooves at southern margin of drift. Bull. Geol. Soc. Am., IJ, p. 457. 85. Guyot, A. 1880. Physical structure and hypsometry of the Catskill mountain region. Am. Jour. Sci., 8rd ser., XIX, p. 429. *94., LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 41 . Heilprin, A. 1907. The Catskill mountains. Bull. Am. Geog. Soc., XXXIX, p. 193. 2 Bice, BR: BB. 1903. Northward flow of ancient Beaver river. Bull. Geol. Soe. Am., XIV, p. 297. . Hubbard, G. D. 1906. Drumlinoids of the Catatonk region. Bull. Am. Geog. Soc., XX XVIII, p. 355. -. Quereau, E. C. 1898. Jamesville lake, N. Y. Bull. Geol. Soc. Am., IX, DD. 176. - Rich, J. L. 1914. Catskill mountains. Bull. Geol. Soc. Am., XXV, p. 68. . Rich, J. L. 1915. Notes on physiography and glacial geology of the northern Catskills. Am. Jour. Sci., 4th ser., XX XIX, p. 137. . Shaw, E. W. 1911. High terraces and abandoned valleys in western Pennsylvania. Jour. Geol., XIX, p. 140. . Tarr, R. S. 1894. Lake Cayuga a rock basin. Bull. Geol. Soc. Am., V, Dp. Bao. Tarr, R. S. 1905. Drainage features of central New York. Bull. Geol. Soe. Am., XVI, p. 229. . Tarr, R. S. 1905. Moraine of Seneca and Cayuga lake valleys. Bull. Geol. Soc. Am., XVI, p. 215. . Tarr, R. S. 1905. Gorges and waterfalls of central New York. Bull. Am. Geog. Soc., XX XVII, p. 193. . Tarr, R. S. 1910. Towns and cities of central New York. Bull. Am. Geog. Soc., XLII, p. 738. . Tower, W. S. 1906. Regional and economic geography of Pennsylvania. Bull. Geog. Soc. Phila., IV, pp. 9, 113, 193, 271; V, p. 21. . Piedmont Folio, U. 8. G. S., No. 28. . Monterey Folio, U. S. G. S., No. 61. . Gaines Folio, U. 8S. G. S., No. 92. . Elkland-Tioga Folio, U. S. G. 8., No. 93. . Brownsville-Connellsville Folio, U. S. G. 8., No. 94. . Waynesburg Folio, U. 8S. G. S., No. 121. . Elders Ridge Folio, U. S. G. S., No. 123. . Rural Valley Folio, U. S. G. S., No. 125. . Ebensburg Folio, U. S. G. S8., No. 133. . Beaver Folio, U. S. G. S., No. 134. . Rogersville Folio, U. 8S. G. S., No. 146. . Accident-Grantsville Folio, U. S. G. S8., No. 160. . Watkins Glen-Catatonk Folio, U. 8S. G. S., No. 169. . Sewickley Folio, U. S. G. S., No. 176. . Barnesboro-Patton Folio, U. 8S. G. S., No. 189. V.—NEWER APPALACHIANS PROVINCE . Baldwin, 8S. P. 1894. Pleistocene of Champlain valley. Am. Geol., XIII, p. 170. . Brigham, A. P. 1905. The great roads across the Appalachians. Bull. Am. Geog. Soc., XX XVII, p. 321. . Chamberlin, R. T. 1910. Appalachian folds of Pennsylvania. Jour. Geol., XVIII, p. 228. *145. *146. ANNALS NEW YORK ACADEMY OF SCIENCES . Clark, W. B., and Mathews, E. B. 1906. Physical features of Maryland. Md. Geol. Surv., Spec. Pub., VI (with geol. map). . Davis, W. M. 1884. The little mountains east of the Catskills. Appal- achia, III, p. 20; also Bull. Mus. Comp. Zool., VII, p. 310. . Davis, W. M. 1889. Rivers and valleys of Pennsylvania. Nat. Geog. Mag., I, p. 183 (also in essays). . Lesley, J. P. 1856. Manual of coal and its topography. . Stoek, H. H. 1901. Pennsylvania anthracite coal field. 22nd Ann. Rept. U.S. 'G. SS; Part Sip; no. . Tower, W. S. 1905. Topography and travel in Pennsylvania. Bull. Am. Geog. Soc, XXXVITI, p. 146. . Williams, E. H. 1894. Extramorainic drift between the Delaware and Schuylkill. Bull. Geol. Soc. Am., V, p. 281. . Willis, B. 1895. Northern Appalachians. Nat. Geog. Soc., Monographs, p. 169. . Willis, B. 1892. Mechanics of Appalachian structure. 13th Ann. Rept. U. SG. 8.; Part 2.) 2081. . Willis, B. 1907. Potomac river basin. Wat. Sup. Pap. U. 8. G. S., No. 192. 1906. Luray caverns. Nat. Geog. Mag., XVII, p. 358. . Harpers Ferry Folio, U. S. G. S., No. 10. . Staunton Folio, U. S. G. S., No. 14. . Piedmont Folio, U. S. G. S., No. 28. . Franklin Furnace Folio, U. S. G. S., No. 161. . Waynesburg-Chambersburg Folio, U. S. G. S., No. 170. . Papaw-Hancock Folio, U. 8. G. S., No. 179. VI.—TrRiassic LOWLAND . Darton, N. H. 1890. Traps of Newark system in New Jersey. Bull. U8.4G. S., No. 67. . Davis, W. M. 1880. Triassic sandstones. Bull. Mus. Comp. Zool., VII, p. 249. . Davis, W. M. 1890. Geographic development of northern New Jersey. Proc. Boston Soe. Nat. Hist., XXIV, p. 365. . Davis, W. M. 1890. Rivers of northern New Jersey. Nat. Geog. Mag., II, p. 81 (also in essays). . Davis, W. M. 1891. Dates of origin of topographic forms on Atlantic slope. Bull. Geol. Soc. Am., II, p. 545. . Hobbs, W. H. 1902. Former extent of Newark system. Bull. Geol. Soc. Am., XIII, p. 139. . Keith, A. 1893. Catoctin belt. 14th Ann. Rept. U. S. G. S., p. 285. . Kiimmel, H. B. 1897. Newark system of New Jersey. Jour. Geol., V, p. 541. . Kiimmel, H. B. 1899. Newark system of New Jersey and New York. Jour. Geol., VII, p. 23. . Lewis, J. V. 1907. Newark trap. Bull. Geol. Soc. Am., XVITI, p. 195: . Salisbury, R. D., and Kiimmel, H. B. 1895. Lake Passaic. Jour. Geol., Pp do: New York Folio, U. 8. G. S., No. 83. Passaic Folio, U. S. G. S., No. 157. LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 43 VII.—O.LpER APPALACHIANS PROVINCE . Barrell, J. 1913. Terraces of northern Appalachians. Bull. Geol. Soe. Am., XXIV, p. 688. . Bascom, F. 1893. South mountain structure. Jour. Geol., I, p. 813. . Bascom, F. 1896. Volcanic rocks of South mountain, Pa. Bull. U. S. G. S., No. 136. . Bascom, F. 1905. Piedmont of Pennsylvania. Bull. Geol. Soc. Am., XVI, p. 289. . Darton, N. H. Economic geology of Richmond. Bull. U. S. G. S., No. 483. . Eaton, H. N. 1912. Geology of South mountain, Pa. Jour. Geol., XX, p. 331. . Geiger, H. R., and Keith, A. 1891. Structure of Blue Ridge near Harpers Ferry. Bull. Geol. Soc. Am., II, p. 155. . Keith, A. 1893. Catoctin belt. 14th Ann. Rept. U. S. G. S., Part 2, p. 285. . Mathews, E. B. 1905. Maryland and Pennsylvania Piedmont. Bull. Geol. Soc. Am., XVI, p. 329. : McGee, W J. 1896. Geographic history of Piedmont plateau. Nat. Geog. Mag., VII, pp. 96, 261. . McGee, W J. 1898. Geographic development of District of Columbia. Nat. Geog. Mag., IX, p. 317. . Shaler, N. 8., and Woodworth, J. B. 1898. The Richmond (triassic) basin. 19th Ann. Rept. U. 8S. G. S., Part 2, p. 385. . Shaler, N. S. 1899. Spacing of rivers with reference to hypothesis of baseleveling. Bull. Geol. Soc. Am., X, p. 263. . Surface, G. T. 1906. Physiography of Virginia. Bull. Am. Geog. Soc., XXXVITI, p. 741. . Tower, W. S. 1906. Regional and economic geography of Pennsylvania. Bull. Geog. Soc. Phila., IV, pp. 9, 118, 193, 271; V, p. 21. . Williams, G. H., and Keyes, C. R. 1891. Piedmont of Maryland. Bull. Geol. Soe. Am., IT, p. 301. . Harpers Ferry Folio, U. S. G. S., No. 10. . Fredericksburg Folio, U. S. G. S., No. 13. . Washington Folio, U. 8S. G. S., No. 70. . Philadelphia Folio, U. S. G. S., 162. . Trenton Folio, U. S. G. S., No. 167. VIII.—CoasTAL PLAIN PROVINCE . Abbe, C., Jr. 1899. Physiography of Maryland. Md. Weather Service, I, p. 41. . Clark, W. B. 1897. Upper cretaceous of New Jersey, Delaware, and Maryland. Bull. Geol. Soc. Am., VIII, p. 315. . Clark and Mathews. 1906. Physical features of Maryland. Md. Geol. ‘Surv., Spec. Pub., Vol. VI (with geol. map). . Darton, N. H. 1896. Artesian well prospects in Atlantic coastal plain. Bull. U. S. G. S., No. 138. . Darton, N. H. 1911. Economic geology of Richmond. Bull. U. 8. G. S., No. 483. 44 *173. 174. ANNALS NEW YORK ACADEMY OF SCIENCES Davis, W. M. 1896. Outline of Cape Cod. Proc. Am. Acad. Arts and " Sei, XX XI, p. 331 (also in essays). Fuller, M. L. 1905. Geology of Fisher’s Island, N. Y. Bull. Geol. Soc. Am., XVI, p. 367. 75. Fuller, M. L. 1914. Long Island. Profes. Pap. U. S. G. S., No. 62. 76. Gilbert, G. K. 1884. The sufficiency of terrestrial rotation for the de- flection of streams. Am. Jour. Sci., 3rd ser., X XVII, p. 427. . Gulliver, F. P. 1896. Cuspate forelands. Bull. Geol. Soc. Am., VII, p. 399. . Gulliver, F. P. 1904. Nantucket shorelines. Bull. Geol. Soc. Am., XV, p. 507. . Harper, R. M. 1911. The Hempstead plains. Bull. Am. Geog. Soc., XLIII, p. 351. . Hitchcock, A. S. 1904. Controlling sand dunes. Nat. Geog. Mag., XV, p. 43. Hobbs, W. H. Lineaments of Atlantic border region. Bull. Geol. Soe. Am., XV, p. 483. . Hollick, A. 1899. Staten Island drift. Bull. Geol. Soc. Am., X, p. 2. Johnson, D. W. 1918. Shorelines and shore topography. McGee, W J. 1888. Head of Chesapeake bay. Tth Ann. Rept. U. S. G. S., p.. 537. ; McGee, W J. 1890. The Lafayette formation. 12th Ann. Rept. U. S. G. 8S., p. 353. . Newsom, J. F. 1899. Effect of sea barriers upon drainage. Jour. Geol., VII, p. 445. Shaler, N. S. 1885. Seacoast swamps. 6th Ann. Rept. U. S. G. S., p. 353. Shaler, N. S. 1888. Martha’s Vineyard. 7th Ann. Rept. U. 8. G. S., p. 297. Shaler, N. S. 1889. Nantucket. Bull. U. S. G. S., No. 53. Shaler, N. S. 1890. Morasses of U. S. and Dismal Swamp. 10th Ann. Rept. U. S. G. S., Part I, p. 255. Shaler, N. S. 1892. Geological history of harbors. 138th Ann. Rept. U. S.G., Sz Part 2, p< 9s. . Shaler, N. S. 1894. Pleistocene distortions of Atlantic coast. Bull. Geol. Soc. Am., V, p. 199. ; Shaler, N. S. 1895. Beaches and tidal marshes. Nat. Geog. Soc. Mono- graphs, p. 137. : Shaler, N. S. 1895. Change of sea level. Bull. Geol. Soc. Am., VI, p. 141. . Shaler, N. S. 1897. Cape Cod district. 18th Ann. Rept. U. S. G. S., Part 2, p. 497. . Spencer, J. W. W. 1903. Submarine valleys of Atlantic coast. Bull. Geol. Soc. Am., XIV, p. 207. Veatch, A. C. 1906. Water resources of Long Island. Profes. Pap. U. 8S. G. S., No. 44. Woodworth, J. B., and Curtis, G. C. 1899. Nantucket, a morainal island. Jour. Geol., VII, p. 226. . Fredericksburg Folio, U. S. G. S., No. 13. Nomini Folio, U. 8S. G. S., No. 23. *201. *202. 203. 204. 205. *206. 207. 208. 209. 210. 211. 212. *213. 214. 215. 216. waif. 218. 219. *220. 221. #222. 223. 224. 225. 226. *227. *228. LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 45 Washington Folio, U. 8S. G. S., No. 70. Norfolk Folio, U. S. G. S., No. 80. St. Marys Folio, U. S. G. S., No. 136. Dover Folio, U. 8S. G. S., No. 137. Patuxent Folio, U. S. G. S., No. 152. Trenton Folio, U. S. G. S., No. 167. Choptank Folio, U. S. G. S., No. 182. IX.—CENTRAL LOWLAND, EASTERN LAKES SECTION Coleman, A. P. 1899. Lake Iroquois. Bull. Geol. Soc. Am., X, p. 165. Coleman, A. P. 1904. Beaches of Ontario. Bull. Geol. Soc. Am., XII, p. 129. Coleman, A. P. 1904. Iroquois beach in Ontario. Bull. Geol. Soc. Am., XV, p. 347. Cushing, H. P. 1908. Paleozoic in northwestern New York. Bull. Geol. Soc. Am., XIX, p. 155. Fairchild, H. L. 1896. Kames of western New York. Jour. Geol., IV, p. 129. Fairchild, H. L. 1896. Glacial Genesee lakes. Bull. Geol. Soc. Am., VII, p. 423. Fairchild, H. L. 1897. Lake Warren shorelines in western New York. Bull. Geol. Soc. Am., VIII, p. 269. Fairchild, H. L. 1898. Glacial waters in Finger lake region. Bull. Geol. Soc. Am., X, p. 27. Gilbert, G. K. 1885. Topographic features of lake shores. 5th Ann. Rept. U. S. G. S., p. 69. Gilbert, G. K. 1895. Niagara Falls. Nat. Geog. Soc. Monographs, p. 203. Gilbert, G. K. 1897. Recent earth movements in Great Lakes region. 18th Ann. Rept. U. S. G. S., Part 2, p. 595. Gilbert, G. K. 1899. Glacial sculpture in western New York. Bull. Geol. Soe. Am., X, p. 121. Gilbert, G. K. 1907. Recession of Niagara falls. Bull. U. S. G. S., No. 306. Goldthwait, J. W. 1910. Isobases of Algonquin and Iroquois beaches. Bull. Geol. Soe. Am., X XI, p. 227. Leverett, F. 1910. Outline of history of Great Lakes. 12th Rept. Mich. Acad. Sci., p. 19. Spencer, J. W. W. 1890. Ancient shore phenomena of Great Lakes. Bull. Geol. Soc. Am., I, p. 71. Spencer, J. W. W. 1891. Post-Pleistocene subsidence vs. glacial dams. Bull. Geol. Soc. Am., II, p. 465. Spencer, J. W. W. 1910. Niagara river and glacial period. Bull. Geol. Soc. Am., XXI, p. 4383. Spencer, J. W. W. 1913. Earth movements about Lake Ontario. Bull. Geol. Soc. Am., XXIV, p. 217. Spencer, J. W. W. 1913. Relation of Great Lakes to Niagara limestone. Bull. Geol. Soc. Am., XXIV, p. 229. Taylor, F. B. 1898. Whirlpool rapids and gorge. Bull. Geol. Soc. Am., TX, p. 59. 46 ANNALS NEW YORK ACADEMY OF SCIENCES *229. Upham, W. 1896. Origin of Great Lakes. Am. Geol., XVIII, p. 169. *230. Upham, W. 1898. Niagara gorge and St. Davids channel. Bull. Geol. Soc. Am., IX, p. 101. _*231. Wilson, A. W. G. 1908. Shorelines of lakes Ontario and Erie. Bull. Geol. Soe. Am., XIX, p. 471. *232. Niagara Folio, U. S. G. S., No. 190. X.—GLACIAL FEATURES . 233. Branner, J. C. 1888. Glaciation in relation to Lackawanna-Wyoming region. Proc. Lack. Inst. Hist. and Science, I, p. 3. *234. Chamberlin, T. C. 1883. Terminal moraine of the second glacial epoch. 3rd Ann. Rept. U. 8. G. S., p. 291. 4 235. Chamberlin, T. C. 1888. Rock scorings of great ice invasions. 7th Ann. Rept. U.S. G. S., p. 147. 236. Chamberlin, T. C. 1899. Cause of glacial periods. Jour. Geol., VII, p. 545. 237. Clapp, F. G. 1908. Glacial period in New England. Bull. Geol. Soc. Am., XVIII, p. 505. *238. Davis, W. M. 1890. Glacial sand plains. Bull. Geol. Soc. Am., I, p. 195. *939. Davis, W. M. 1892. Catskill delta in Hudson estuary. Proc. Bos. Soc. Nat. Hist., X XV, p. 318. *240. Fairchild, H. L. 19138. Pleistocene geology of New York. Bull. Geol. Soe. Am., XXIV, p. 133. *241. Goldthwait, J. W. 1913. Glacial cirques near Mt. Washington. Am. Jour. Sci., 4th ser., XX XV, p. 1. 242. Goldthwait, J. W. 1913. Following the trail of the ice-sheet and valley glacier on the Presidential Range. Appalachia, XIII, p. 1. *243. Johnson, D. W. 1917. Date of local glaciation in the White, Adirondack, and Catskill mountains. Bull. Geol. Soc. Am., XXVIII, p. 548. *244, Lewis, H. C. 1882. Great terminal moraine across Pennsylvania. Proce. Am. Assn. Ady. Sci., XX XI, p. 389. *245. Ogilvie, I. H. 1902. Glacial phenomena in the Adirondacks and Cham- plain valley. Jour. Geol., X, p. 397. *246. Rich, J. L. 1906. Local glaciation in the Catskill mountains. Jour. Geol., XIV, p. 118. 247. Salisbury, R. D. 1909. Physiography of the Pleistocene. Jour. Geol., XVII, p. 589. *248, Upham, W. 1894. Englacial drift. Bull. Geol. Soc. Am., V, p. 71. 249. Upham, W. 1899. Epeirogenic movements causing the ice age. Bull. Geol. Soc. Am., X, p. 5. XI.—STATE REPORTS New York The present publications of the State Geologist are distributed as bulletins of the New York State Museum and cover the geology of various quadrangles and regions and special topics. A complete list may be found in almost any one of the recent bulletins. The most important ones are the following: Nas- sau County and Queens, No. 48; Canandaigua and Naple quads., No. 63; Little LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 44 Falls region, No. 77; Watkins and Elmira quads., No. 81; Tully quad., No. 82; Mooers quad., No. 83; Schoharie region, No. 92; Northern Adirondacks region, No. 95; Paradox Lake quad., No. 96; Buffalo quad., No. 99; Penn Yan and Hammondsport quads., No. 101; Rochester and Ontario Beach quads., No. 114; Long Lake quad., No. 115; Portage and Nunda quads., No. 118; Remsen quad., No. 126; Geneva and Ovid quads., No. 128; Port Leyden quad., No. 135; Au- burn and Genoa quads., No. 187; Thousand Islands region, No. 145; Pough- keepsie quad., No. 148; Honeoye and Wayland quads., No. 152; Broadalbin quad., No. 153; Schenectady quad., No. 154; North Creek quad., No. 170; Syra- cuse quad., No. 171;.Attica and Depew quads., No. 172; Lake Pleasant quad., No. 182; and especially : *250. Berkey, C. P. 1907. Geology of the Catskill aqueduct. Bull. N. Y. State Mus., No. 146. *251. Grabau, A. W. 1901. Geology of Niagara Falls. Bull. N. Y. State Mus., No. 42. +952. Miller, W. J. 1913. Geological history of New York State. Bull. N. Y. State Mus., No. 168. New Jersey The publications of the geological survey of New Jersey are comprised in a series of bulletins, the first one appearing as Bulletin 1 in 1910, and in a series of final reports, thus far eight in number, the first one being that issued in 1888. The most important of these are: 253. Report of State Geologist, 1888. I. (Topography, with shaded relief map.) P *254. Report of State Geologist, 1895. IV. (Physical geography.) *255. Report of State Geologist, 1902. V. (Glacial geology.) #256. Lewis, J. V., and Kiimmel, H. B. 1915. Geology of New Jersey. Bull. N. J. State Geol. Sury., No. 14. (Summary and description of the geological map, 1910-1912, scale 1: 250,000. ) New Hampshire Lo Ol =I . Hitchcock, C. H. 1874. Geology of New Hampshire. Vermont The available reports to date of the Vermont State Geologist run from Vol. I to Vol. X, each covering two years from 1897 to 1916. They are well illus- trated and occasionally contain geological maps of local areas. Several sec- tions treat of glacial features, local and continental. Connecticut The present publications of the Connecticut State Geological and Natural History Survey are issued as bulletins, No. 1 appearing in 1903. The most important physiographically are: *258. Barrell, J. 1915. Central Connecticut in the geological past. Bull. Conn. Geol. Surv., No. 23. 48 ANNALS NEW YORK ACADEMY OF SCIENCES *259. Rice, W. N. 1906. Manual of geology of Connecticut. Bull. Conn. Geol. Surv., No. 6. Pennsylvania The most important reports of Pennsylvania are those of the Second State Geological Survey, comprising a long series of volumes covering the geology of the various counties, together with annual and special reports, of which the following deserve special note: *260. Lewis, H. C. 1884. The terminal moraine in Pennsylvania and western New York. Second State Geol. Surv. Rept. Z. ‘(This report includes a simple hachure map showing the topography of the State.) 261. Final summary report in three volumes, 1895. (With general index printed separately, and atlas in folder containing geological map of Pennsylvania. ) 262. Ashburner, C. A. 1885. Archbald pot-holes. Ann. Rept. Second State Geol. Surv., 1885, p. 615. The present publications are the reports of the Topographical and Geolog- ical Survey Commission. Report I appeared in 1910. These are usually local and economic in character. Maryland The present publications of the Maryland Geological Survey appear as re- ports running from Vol. I, 1897, and in addition a series of volumes in the same uniform style, dealing with the systematic geology of the State, but not definitely numbered. They are arranged according to counties and geological horizons. The reports of the Maryland Weather Service run from Vol. I, 1899, and comprise to date three or four volumes containing helpful physiographic material. The following deserve special note: *263. Abbe, C. 1899. Physiography of Maryland. Rept. Md. Weather nervy ice, I. 264. Rept. Md. Geol. Surv., 1897, I, p. 148. (Physiography.) *265. Rept. Md. Geol. Surv., 1906, VI, p. 55. (Physiography.) Virginia The publications of the State Geologist are embodied in a series of bulletins. These are usually economic in character, but the following may be particularly noted : . *266. Clark, W. B., and Miller, B. L. 1912. Physiography and geology of the coastal plain province of Virginia. Bull. Vir. Geol. Surv., No. 4. XII.—GEOoLOGICAL Maps 267. Geological Map of North America. 1911. Scale 1: 5,000,000 (with Profes. Pap. U.S. G. S.No: aaa: 268. N. Y. Geol. Map. 1901. Scale 1 in. —5 mi. 269. N. J. Geol. Map. 1912. Scale 1: 250,000. LOBECK, NEW YORK CITY, A PHYSIOGRAPHIC CENTER 49 . Conn. Geol. Map. 1907. No. -7). 272. Penn. Geol. Map. 1893. Penn. Geol. Sury.). . Md. Geol. Map. 1907. 70. Mass. and R. I. Geol. Map. 1 1916. Scale 1: 250,000. Scale 1: 250,000 (with Bull. Conn. Geol. Surv.. Seale 1 in. = 6 mi. (with final report of Second 3 Scale 1: 500,000. 4. Virginia Geol. Map. 1916. Scale 1: 500,000. XIIT.—SELEcTED List Fifty topographic maps covering practically all of the regions outlined for field work may be obtained from the Director of the U. S. Geological Survey, Washington, and will cost, when ordered in lots of 50 or more, 6 cents each. New York: Niagara Falls Luzerne Bolton Glens Falls Catskill Kaaterskill Rosendale Poughkeepsie ~ Harlem Paterson Staten Island Brooklyn Oyster Bay Clyde Plattsburg New Jersey: Plainfield Hackettstown Sandy Hook Delaware Water Gap Atlantic City Long Beach Barnegat Pennsylwania: Harrisburg New Bloomfield Hollidaysburg Maryland: Harpers Ferry Washington Maryland (continued ) Papaw Hancock Frostburg Virginia: Norfolk Luray Maine: Portland Casco Bay Massachusetts: Provincetown Wellfleet s0ston Boston Bay Housatonic Taconic Marthas Vineyard Nantucket Connecticut: Meriden Middletown New Hampshire: Mt. Washington Gorham Crawford Notch North Conway Monadnock — Peterboro The following folios are still in stock at prices named: Niagara, No. 190, 50 cents; Raritan, No. 191, 25 cents; Papaw-Hancock, No. 179, -_ 5 cents: Watkins Glen-Catatonk, No. 169, 5 cents; Choptank, No. 182, 5 cents. Pate ee CN ee ie es =e eA Ele ee Re Se ae re aor ae oe * 9, - *. a tate a. end oe on x ANNALS OF THE NEW YORK ACADEMY OF SCIENCES : Vol. XXVIII, pp. 51-166, pil. I-XIII hapa Editor, RatpH W. TowrErR if __A MEMOIR ON THE PHYLOGENY OF THE ‘ JAW MUSCLES IN RECENT AND FOSSIL VERTEBRATES BY LEVERETT ALLEN ADAMS NEW YORK PUBLISHED BY THE ACADEMY ail 15 JANUARY, 1919 THE NEW YORK ACADEMY OF SCIENCES (Lyceum or Natura History, 1817-1876) _ Orricers, 1919 Ee President—Ernust Exvtsworrn Suiru, 50 East 41st Street Vice-Presidents—GurorcE B. PearamM, FranK H. PIKxz, < KpMuND QO. Hovey, Piiny E. GopparpD # « Daorresronding Secretary—Henry E. Crampton, American Museum ~~ Recording Secretary—Ratepu W. Tower, American Museum == Treasurer—JOHN TaTLocK, 37 Wall Street i a Librarian—RatrxH W. Tower, American Museum Editor—Rauru W. Towser, American Museum SECTION OF ASTRONOMY, PHYSICS AND OHEMISTRY Chairman—GeorGE B. PEGRAM, Coie University Secretary—K. Grorce Faux, Harriman Research Laboratory, the Roosevelt Hospital SHOTION oF BIOLOGY Chairman—F rank H. Prxe, College of.Physicians and Surgeons ey K. Gregory, American Museum SECTION OF GEOLOGY AND MINBRALOGY Chairman—Epmunp O. Hovey, American Sawertin Secretary—Cuarues C. Moox, American Museum SECTION OF ANTHROPOLOGY AND PSYCHOLOGY e C Chairman—Puiny E. Gopparp, American Museum Secretary—Rosert H. Lowin, American Museum The sessions of the Academy are held on Monday evenings at 8:1! o'clock from October to May, inclusive, at The American Museum oe Natural History, 77th Street and Central Park, West. te a botarl oss * Dus e ’ iy ~~ i ~ r rah Pe ae an, me meg age AAP NO 1 sta te : frat we Sei gee ee We aw Off Sots ea Mie > Se vig Pa iby hyd ah SES 2 SDP ae eS PR ERIM, Delaware Water GaP iff" ™ TEM i Ss > > ei eae, ~ os ay canes Lee ROS WY ttetown > Oo% Ss esa aa od Sen JN chootey al => - eN x A i 4 3e > > 3S $ ty we Se Sn IN ayy’ Ss outage NG NS Long Hill sid i Ra ee ee Cirrannit ntheeet nae SS Pri SN * < Pw inichug fore = han pe ye TM aoe iN \ » = ~ 41 We RIN. Seconds wate banal Recah i Ys ensack Ri £oe Bees (G10 CR Passa PX 9 aes sagee Ui aca , yor SS ourland Mountain S CT Mian Wen we De a SLAIN UDP 3 Rs ZOU Ane Lee Aa Nae 1 Hea : . | \ : at le aS Ne sinh ng a irc IDOE MLZ Wee a Se > Passaic Pass: ry Mis ? x iS Lf Oa. or ’ A NS MAAS 8 Quy =, 2a * a ~ TOA “ Se ay, Ree a ; SNS 3 gD RS —— - Tye a MSD REE RTS NS N Si ta < : eat ONS a Tans aero, Pe a ert? SS SS SFT eet Gare! e : oes Nw ~ 2 as Sane ays ays SS dS Nee ee a Mina nsaa SEIS ee Terminal pq oS Ta. ors 7, Five physlogtaphic provinces are MGpeUA RAT IAGL 07 This AMagran, Ql! of them forming belts trending In a northeast —Southwest Ajrection. 4A small portion of the Allegheny laléad Province appears al the_/op, along, thé right bank of the Delaware River. 70 the west of Delaware ™ Water Gap it is known as the Pocono. Plateau and farther forth jn New York it Forms the Catskill Mins. 2. The bel? of Newer_or Folded alachians 1s atrower here than at any orher point. Aittatinny Mountain 13 the most krominent ridgé,and is of the monociinal type, EY westward. The broad valey 7o the €asiward, known here as the Hitalinny ar Wallttill Valley, 1a pat? of the Creal Jippalactian Valley. ~ I 3. The bel? of crystalline rocks Horiming the New Jersey Highlands Ipay be seen exer ng trom the Gage the Hadson SONG ly AGTOS'S thé state and inio SHSNGUA: ecause If ends al Fre go, Gt LEcause ‘? 1s really an exiension oF the (ar. l it is Known as the Feeadin CB) of the New England Yoland. _ & The next belt, the Triassi€é Low, 1s developed upon a series of sandsiones infaulted or downwarped into the older crystallines, The interbedded and resistanr Wap_sheels determine Such pronounced features as the Fulisades and Warchang Fidges. S. The rést of the area Is embraced in the cogsle (fain Frovingce whose™ cuesla may be seen extending From the Navesink or Atlantic Highlands southward where /- forms the hilly belt of “southern New Versey- Fig.29 BLOCK DIAGRAM SHOWING ihe REE SSEATUIRES OF NORTHERN NEW JERSEY COPYRIGHY 1917 Armin K Lopeck CoL_umMBiaA ONIVERSITY ‘ a — _ Se et cee: te Oe ~ Mery ¢ [ANNALS N. Y. AcaD. Sct, Vol. XXVIII, pp. 51-166, Pls. 1-X 15 January, 1919] A MEMOIR ON THE PHYLOGENY OF THE JAW MUSCLES IN RECENT AND FOSSIL VERTEBRATES 2 By LEVERETT ALLEN ADAMS (Presented before the Academy, 8 March, 1915) CONTENTS Page i i ee ok sak emi heamalaieoais 52 ae IMR ANT TR TOC™ DMMP RIRIRESTNY oo a's ni 5) tue wn, op ale aX eye atte vivid. oe scare wine x 55 en an MIREAON INR Rega) ts we ei ec we cbs See vn a e-ws ewblvawhe wane 55D ERED, 6 oe su pS as dale en wide a's 6 44 a's SNe ae Le eee 55 OE CINE Ne Eee ees Siva kc we Sb ale wb ee TER eee PO ee eee 56 aera aa IND aM IRSA 3 ., (a) ea" eS ra ed 0 4k. < Si duhvwsallal’S’ oo mate wie ann & eee 60 RNR IE ia lth At IM So cae ge Winn ini’ pitas. a a v, nloofe aah alah worms cadhs 60 MERE EMMETT teh rarer a OMS. rng cide acd Gara asa bik Bi mye wid jab. 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Pts ole See co. d wikecla bake dnc dw URb Se wales 78 tee MERA TM ELIMITE Vila. lysine) pv din and u'W a 0 Bin Sled Ale dw be ole wiele® 80 ee es aha ie ve qb uale e's eine ore we sie 83 RN ST ann rae ar atv cot 4, ae oliegaves> one tho of ¥ 0g a:8'> « njnp ete op 83 p ce BE UP EER filo RS SS Dee ee a MR 2. ae SMe oe ae ce ee cis os eh ee eweee aa Oh Coma Gate 86 ] em OI ED Wt tk bles ie Wg wid eae’ Bark aoe «wa ctw before do yl @iatle e oeeun’ 88 4 SIS 2 ip casks Lee he ie wi es Pere Seis i dks pee aidal.. Vonbberel er ike 88 ’ rae aa is Soria y: c.inaiy arse min in wi cle a sab whe wo ge 88 eo ee ee ae eee D iiiecg a5a- oie tne COE hie at RTS ee eat 90 ee eee Me ikaw ks ding ks wh pd ies Kms be hep ows cee 92 PMRW a a Pade oeic kde gb wos vena be ees a Sua Ne. Vee a gimiale mens Se 95 eS SRS Pe es een Se ee se teeees 97 PMR Shes cs diaiiess SERS ite with, wai aA whet e e's Rabe Naot sa taiel Ska techs Sie, « 99 EN REE OE ee ee Se a 99 1 Studies in Comparative Osteology and Myology, No. 2, issued under the direction of Dr. William K. Gregory, Assistant Professor of Vertebrate Paleontology, Columbia Uni- _ versity, and Research Associate, American Museum of Natural History. (51) 52 ANNALS NEW YORK ACADEMY OF SCIENCES : Page IVE UA TUT D A Sogn WES As ctnip 0 x die Rade wis RoI ROU Reet MAN te g nd oes oe ee 102 AEORGEMOMES 5 <5 Wiicinie Saleh oe be ee (pl ein Ris ip telanacel aroire cs) = leeks ta aa ek PHGD CUTS 65 6 es 6g ask ae idle sade Rips Wega ga eae Peta alee 115 SOLCROGOM ss oo ices 5 nkcclsie sie sles ste cee om atee Ole Oe ee oe 148 Homology in the Mammalia. ...é..6<.00< 205) Yeas da cco eee ee 149 General summary of homologies: . 0) 00.6 fuss ww oe oes fs ae ee 153 Relations of jaw muscles to the temporal fenestre of reptiles........ 154 Tables I-V summarizing the homologies of the jaw-elements in Fishes, Amphibia, Reptiles, Birds, Mammals and Vertebrates as a whole... 156 Bibliography . .. 22+... Sowicbiepa ave tn’ a%at aw iGhe) dates aia eAa! slalatg tana oe, Slee 6 aan a 160 INTRODUCTION This paper attempts first to trace the muscles of mastication from their origin in the primitive gnathostomes to their perfected development in the higher vertebrates and secondly to discover the co-adaptations of musculature and skull structure. There has been a great neglect of the correlation between osteology and myology. Hundreds of monographs are at hand on both subjects, yet synthetic studies that deal with both and with their interrelationships are extremely rare. As muscle was no doubt in existence before bone, and as there is the closest relation between the two, we should naturally con- sider myology and osteology together instead of under separate heads. Many monographs have been written on the myology of special forms, but usually with little consideration of the conditions to be found in related groups. Apart from the great work by Ruge on the seventh nerve, there have been few general surveys attempted. Ruge traced the facialis nerve and its musculature from the elasmobranchs to mammals, giving ADAMS, PHYLOGENY OF THE JAW MUSCLES 53 us one of the best types of comparative work at present available. Toldt, Bijvoet, Chaine, Rouviere, Parsons, Dobson and others have traced the digastric muscle in the mammals, giving homologies and tracing the muscle to its origin in the lower forms. The many writers on the muscles of special groups have used synonymous names and the nomenclature is far from clear at the present time. Many names for muscles are used in special cases that might well be changed to give a more uniform system. The influence of the musclature upon the evolution of the skeleton in vertebrates has also been neglected in most of the general works on com- parative anatomy. Much has been written on the changes that have taken place in the skulls of the vertebrates, but with too little reference to the muscles. The paleontologists and anatomists have traced the shiftings and changes of each bone in the skull so that the migrations of the hyomandibular and of the quadrate, for example, are known from the time when they appear as cartilages in the selachians to their final resting place in the mammalian ear. Thus during the last decade or two oste- ology has made great progress as an interpretative science. From the work done on the fossil forms the evolutionary history of the skeleton is not nearly so obscure as it was a few decades ago. The structure of many of the fossil forms is being gradually worked out and some of the great vertebrate phylogenies are being cleared up by the recent developments in paleontology and comparative anatomy. Tor example, the relatively close relationship between the reptiles and the amphibians is becoming very clear, for the discovery of new Carboniferous forms has added much to our knowledge, so that more and more structures common to the two classes have been observed. The same applies to the relationship of rep- tiles and mammals. The recent discoveries in South Africa of a number of new cynodont reptiles have given much new light on the evolution of the mammals from the reptilian stock, so that great advances have been made in the early history of these relatively modern groups. Many morphological problems, such as the problem of the mammalian pterygoid and its origin, of the ossicles of the ear, of the development of a new joint on the dentary, and its new articulation with the squamosal, have received illumination from the synthesis of paleontology and comparative anatomy. In all such studies the great working tool of the paleontologist is comparative anatomy, as without it he is helpless to determine the relationships of the fossil forms, just as the student of modern forms is helpless if he attempts to work out the relationships of the modern fauna without considering the maze of ancestral types that preceded them in the past. Thus the importance of the modern forms is demonstrated every day in the great museums of paleontology and comparative anatomy 54 ANNALS NEW YORK ACADEMY OF SCIENCES where many of the new discoveries are due to the synthesis of the study of present forms with those of the past, so that a department of paleon- tology should combine in its collections a complete series of the modern with the fossil forms, if correct interpretations are to be made of the fossil material. The factor that has been most neglected has been the study of the myology along with the bony structure of the fossil forms. ‘The bones of the skeleton should be studied not as independent elements, but as supports for the muscles that covered or were attached to them. The skull of an ophidian studied merely as an osteological specimen shows much in the way of specialization and peculiar development, but without the study of the motive power for which it furnishes the support the results are rather barren, as too much has been left out of consideration. It is like making a study of a complex series of levers without taking into consideration the forces that move them. A few papers and books do indeed consider the correlation of the bones and muscles in modern forms, especially man, such as Bardeleben (1903), Fick (1904-1910- 1911), Strasser (1908). These studies on modern forms give the key for similar work on the fossils, as the principles of mechanics concerned hold throughout. Prof. W. K. Gregory (1912) has endeavored to correlate paleontology, osteology and myology in his studies on the evolution of the hmbs of recent and fossil ungulates. Huis discussion of the angle of in- sertion of the muscles upon the limb bones, in relation to power and speed, bears upon the study of jaws and jaw muscles. Realizing the need of further studies of this kind, Dr. Gregory suggested that I should take up the problem of the evolution of the jaw muscles of vertebrates in rela- tion to skull structure. In this paper I have accordingly had before me the following aims: first, to follow the jaw muscles through a selected series of vertebrates ranging from shark to man and to express the essential facts in clear and semidiagrammatic drawings of uniform character and treatment, to facili- tate comparison; second, to discover and summarize the homologous re- lations of the several jaw muscles throughout the series and thus attempt to clear up and harmonize the confusing synonymy due to varying systems of nomenclature founded on special types; third, to discover the adapta- tional relations between skull structure and musculature; fourth, to apply these principles to a reconstruction of the musculature in certain extinct vertebrates, especially those of great general phylogenetic importance in the different classes. ADAMS, PHYLOGENY OF THE JAW MUSCLES BB STATEMENT OF THE PROBLEM The problems of the musculature of the jaws and of the homology of these muscles throughout the vertebrates are of great potential impor- tance in the future development of comparative anatomy. As the jaw muscles are concerned in all the movements of the skull and have de- veloped with it, their influence in modifying the skull in the early history of the vertebrates is well worthy of detailed study. The jaw muscles also offer much of interest in their relation to the origin and evolution of the dentition and in the evolution of the mammalian skull from the reptilian type. Such great themes as the origin of the mammalian auditory ossi- cles, the origin of the peculiar mammalian articulation of the mandible with the squamosal, the transformation of the reptilian jaw into the mammalian type, and the homology of certain skull bones in different groups are also involved. The mechanical problems connected with the specialized jaw movements of some of the higher vertebrates are also interesting, especially in cases where the close relation of the jaw muscles and the specialized skull structures are readily discovered. The jaw mus- cles are also sometimes of value in testing relationships of closely related groups, especially where specialization has not gone so far as to obliterate all the primitive conditions, since with a few exceptions the arrangements of the jaw muscles are remarkably constant in fundamental characters in each of the vertebrate classes. CRITERIA OF HomMoLoGy The problem of homology in the muscular system is a most difficult one, as the muscles are very unstable elements, given to shifting their positions, splitting up into fragments, and combining with other elements like themselves. There are four tests that may be applied to a niuscle to determine its possible homology with a similar muscle in another animal: (1) embry- ology, (2) nerve supply, (3) origin and insertion, (4) function. If all of these agree there is great probability that the homology. assumed is correct. EMBRYOLOGY Embryology is helpful in determining origins and in giving a clew, at least, to the relations of the muscle. Keibel and Mall (1910) in their Human Embryology show that primitive relationships are evident in cer- 56 ANNALS NEW YORK ACADEMY OF SCIENCES tain early stages of development. They describe the origin of the human jaw muscles that are innervated by the fifth nerve as follows: In the 7 mm. embryo the mandibular arch is filled with a closely packed mesenchyme, with only slight traces of condensation about the peripheral end of the mandibular nerve. In the 9 mm. embryo, however, this condensation is clearly to be recognized. This peripheral mass, in which the N. mandibularis ends, lies at about the middle of the arch. In a 11 mm. embryo, this egg- shaped pre-muscle mass has increased in size but still shows no indications of splitting into the various muscles. The pre-muscle is, from the beginning, closely associated with the condensed mesenchyme of the mandible, and with the differentiation of the proximal end of the mandible, the pre-muscle mass is partially split into a Y-shaped mass, the handle representing the M. temporalis, the outer limb corresponding to the M. masseter, and the inner, deeper limb, separated from the outer by the proximal end of the mandible, representing the mass for the Mm. pterygoidei externus and internus. Thus it is seen that all these jaw muscles arise from the same group. The relations of the jaw muscles to the body muscles as a whole are as follows: In the early stages of the vertebrate embryo the myotome is a hollow body with a splanchnic inner layer and an outer or somatic layer. This myotome grows down until it almost meets its fellow on the opposite . side, the two remaining separated from each other by a connective tissue septum, the linea alba of the fishes. The myotome is also divided by a longitudinal line of connective tissue that follows along the lateral line of the fishes and the urodeles and divides the myotome into a dorsal or epaxial epimere and a ventral or hypaxial hypomeré. 'The muscles of the body are accordingly divided into three groups—appendicular, axial and visceral. The appendicular muscles take their origin from the axial, and both in turn are derived from the dorsal or epaxial (epimere) part of the myotome. The visceral muscles, including those of the head region, are derived from the ventral or hypaxial portion of the myotome (hypo- meres). (Wilder, 1909, p. 190.) The visceral or hypaxial muscles of the head region are further divided into a dorsal and a ventral series according to their position as depressors or levators of the gill arches. NERVE SUPPLY The primitive innervation of the myotomes in Amphtorus is shown by Goodrich (1909, p. 2). The myotomes are supplied by the ventral roots of the serial nerves, the dorsal roots passing between the myotomes to supply the skin and the sensory nerves. The dorsal and ventral roots of the serial nerves remain separate. Regarding the innervation of typical vertebrates Goodrich (1909, p. 3) says: ADAMS, PHYLOGENY OF THE JAW MUSCLES 57 It is important to notice that while the myotomes and the muscles derived from them (such as the limb muscles) receive their motor nerves exclusively from the ventral roots of the spinal nerves, the splanchnic muscles, the skin, the mucous membrane and their sense organs are supplied by the dorsal, ganglionated roots. The embryology of Petromyzon, Amphioxus and the fishes give some very illuminating evidence of the evolution of the muscular and the nervous system in the early vertebrates, and from them we may get a better understanding of the muscles and serial nerves of the higher vertebrates. Thus a study of the embryology gives much aid in tracing the homology of the capitimandibularis muscle in the reptiles, where it is an undiffer- entiated mass, as in the embryo of man. Again the problem of the musculature of the middle ear is very much clarified by the embryological investigations of Gaupp, Versluys, Fuchs and other students of the ear, where the development gives an explanation of the origin of these ele- ments. As the nerves and muscles start out together very early in the life of the embryo, the nerve supply has always been taken as one of the best tests of homology. It is almost an axiom in comparative anatomy that a muscle is always followed by its nerve, and while in most cases this is true, it is occasionally not true. The stapedius muscle of the middle ear illustrates the constancy of the nerve supply. This muscle is followed from its position as a levator of the hyoid arch through many changes to its final resting place in the middle ear, with the innervation by the facialis remaining constant. The tensor tympani muscle also represents a slip of the reptilian pterygo-mandibularis that has shifted to the middle ear. The facialis in its migration from the hyoid arch over the face gives another fine example of the constancy of the nerve supply to the muscle. In man the platysma, sphincter colli and facial muscles of the eye, nose and mouth have migrated from their original position on the side of the neck to the most anterior portion of the face. In this case the seventh nerve has overlapped the territory of the trigeminus and the serial nerves anterior to it, while the muscles of the fifth nerve have remained in their original position. The pectoralis and latissimus dorsi muscles of man give another example of shifting muscles that carry their nerves with them. They shift from their original position to cover large areas of the trunk that were formerly innervated by the several serial nerves of the myotomes. In the external oblique of man and the rectus abdominis there is a fusion of the elements, their originally separate condition being shown by their nerve supply. The digastric is also a muscle with a double nerve supply, and is very 58 ANNALS NEW YORK ACADEMY OF SCIENCES probably a muscle with a double origin, since it originally has two bellies, the anterior innervated by the fifth nerve and the posterior belly by the seventh. In spite of some seeming contradictions, the nerves offer the best means of determining homologies in the muscles. Wilder (1909, p. 196) says: Were it possible to follow each motor nerve fiber from its origin to its con- nection with its muscle, it would probably serve as an absolute eriterion for muscular homology, but there is a chance for error in the fact that an ana- tomical nerve is not a single fiber, but a bundle of them, and while each fiber is presumably constant in its supply, there is some variation in the way in which they are put into bundles, so that no one can be sure that a given nerve is quite homologous with one in a like location in another animal. Most anatomists agree with Wilder’s statement of the case. We may suppose that these changes of the contents of the bundle are responsible for some of the examples of apparent non-homology that often occur in animals that are closely related. We may assume that in the original condition of the vertebrates the myotomes were placed in regular order and each myotome was supplied with a serial nerve. With the gradual changes that took place in development the higher vertebrates disguised the metameric arrangement until only slight remnants of them remain in a few muscles like the obliquus externus of man. The myotomes are evident through the fishes and tailed amphibians, but are not so evident in the reptiles and mammals. The elements of certain of the myotomes usurped the position of the others and developed into the larger muscles of the trunk, carrying with them their original nerves, thereby destroying the primitive arrangement. In a paper by D. J. Cunningham (1891) the problem of nerve and muscle is very carefully considered. He considers the nerve supply a good guide but not an infallible one. He says that a solution of the problem can only be obtained by approaching the question from two points of view: first, by studying the early connections which exist be- tween the nervous and the muscular system in the embryo; second, by examining one or more groups of muscles, the homologies of which are undoubted, in a large series of animals or in a large number of indi- viduals of the same species, and observing whether in every case the nerves of supply are the same. ) In many cases the nerves are found fusing into a plexus. Cunning- ham’s paper favors the view that the same ganglion cells are invariably connected with the same muscle fibers, but that the fibers may adopt a different path and thus reach their connection through another route. This seems incapable of proof, but it is a good working hypothesis. He ADAMS, PHYLOGENY OF THE JAW MUSCLES 59 mentions two cases worked out by Sir William Turner where the long buccal nerve proceeded from the superior instead of the inferior maxillary of the fifth nerve. He also gives some observations of his own on Elephas, Hyrax, and Castor, where the internal plantar nerve invades the terri- tory of the external plantar and seizes upon muscles which usually do not belong to it. In the fox-bat the opposite occurs and the external plantar lays hold upon a muscle which under typical conditions is con- trolled by the internal plantar. This piracy of the nerve terminals finds its analogue in the capture of branches of the carotid, as described by Tandler. This may well be considered a changing of the paths of the fibers and not a change of the ganglionated cells and of the muscle fibers. In the case of certain muscles of doubtful homology in Ornithorhynchus Ruge has shown a substitution of the nerve supply from a different plexus from that which supplies the supposedly homologous muscles in other mammals. He solves the problem by deciding that the muscles concerned are not homologous. Gadow gives some cases of truly homologous muscles being supplied in different types by a different plexus. He shows that, in Iguana, the ischio-femoral muscle is supplied by the ischiadic plexus; that in the Crocodile it is supplied by another nerve, the obturator; while in Varanus it is supplied by both. In placental mammals the adductor magnus is innervated by two nerves, one from the obturator nerve and one from the sacral plexus. In marsupials the adductor magnus is supplied solely by the sacral plexus. | Cunningham offers the following possible explanations of these anoma- lies: | (1) Complete obliteration, and then complete reconstruction of both nerves and muscles, the muscle assuming its old origin and insertion. (2) Retention of both nerve and muscle elements but the adoption of new and more convenient paths. (3) A retention of the muscular elements but a substitution of new nerve elements. He rejects the first, does not give much consideration to the third and seems to agree with Fiirbringer “that the nerve supply is the most im- portant and indispensable guide but is not infallible.” Goodrich (1909, p. 82) concludes that, “in a series of metameric myo- tomes and nerves each motor nerve remains, on the whole, faithful to its myotome throughout the vicissitudes of phylogenetic and ontogenetic modifications.” In the case of the jaw muscles experience shows the great importance of the nerve supply in determining the homologies of muscles. 60 ANNALS NEW YORK ACADEMY OF SCIENCES ORIGIN AND INSERTION The origin and insertion of the muscles must be taken into considera- tion in the determination of their homologies, but as some of the skeletal elements shift and drop out in the different classes, this criterion must be used with care in cases where the animals compared are not closely related. The known changes and disappearance of the bones of the skull as we pass from Palseozoic to modern vertebrates suggest that, if the sup- posed homology of a muscle is based on the origin and insertion, the history of the bone to which it is attached must be known and completely traced; for example, in tracing the changes that have taken place in the remodeling of the cynodont skull, in its evolution into the mammalian type, there is difficulty in following the origin and the insertion of cer- tain muscles, as the shifting of bonés is so marked in the jaw region that some muscles have changed their origin and insertion and some have dropped out and been replaced by slips from neighboring muscles. Al- though it seems reasonable to infer that muscles became readapted, yet if there was a mechanical or other reason for the dropping out of a muscle we may assume that a new slip was separated from another muscle that filled the requirements of the new function. Great changes from the primitive reptilian type must have taken place in the line leading to Cynognathus, Gomphognathus and Sesamodon. The posterior end of the dentary increased in importance and the coronoid process of the dentary gradually overshadowed the posterior end of the mandible as an attachment for muscles, so that muscles formerly attached to the sur- angular and to other posterior bones of the jaw moved forward and acquired an attachment on the upgrowing coronoid process. Finally the reduced muscles of the movable pterygoid of the reptiles must have shifted, disappeared or possibly be left as remnants such as the pterygo- spinosus of the edentates or the pterygo-tympanic that is sometimes found in man. FUNCTION The jaw muscles are on the whole remarkably stable throughout the vertebrates with minor adaptive changes. The larger muscle masses can be traced through the different classes, but some of the minor slips must be followed closely in their development through a number of forms if the homology is to be certain. The history of the changes of function can be traced from their innervation and their relation to their supports. The fact that they are derived from the visceral muscle system indicates ADAMS, PHYLOGENY OF THE JAW MUSCLES 61 that they arose as muscles for contracting and dilating the gill openings, drawing in water containing food and oxygen, and finally that they were used in snapping at prey (Gregory, 1915). The predatory habits of the primitive fishes were responsible, it is believed, for the change of the gill muscles into true jaw muscles. Even in mammals the muscles are still intimately related with the branchial arches, with the tongue and even with the ear. The point of attachment and the function of a mus- cle must then be considered as one of the available criteria of homology. This should always be considered when the history of the bone to which the muscle is attached has been thoroughly studied through a number of classes and when also its developmental history is certain. Neomorphs have often arisen as slips from some of the muscles; muscles frequently have split up into slips that eventually have become separate and taken a part of the parent nerve with them as in the ptery- goids of the mammals. We have numerous examples of this splitting: for example, the derivation of the anterior belly of the digastric of mam- mals from the mylohyoid, or the subdivision of the “adductor mass” into numerous slips in Amia. If this splitting is carried further and the slips separate, it becomes correspondingly more difficult to trace their homology. ACKNOWLEDGMENTS This work has been carried on in the Department of Vertebrate Paleon- tology at the American Museum of Natural History, under the general direction of Professor W. K. Gregory, from whom the author has con- stantly received critical suggestions and helpful advice. I am also grate- ful to Professor R. C. Osburn for the loan of private material used in a part of the work on the teleosts; and to Mr. J. T. Nichols for other speci- mens of fish needed in the teleost series. To Dr. L. Hussakof my thanks are due for his placing at my disposal numerous specimens from the col- lection of Arthrodira in the Department of Ichthyology. Finally, in common with many other investigators, I am mindful of a larger debt to the American Museum of Natural History for liberty to use its extensive resources. , A series of 26 existing types of vertebrates has been dissected as fol- lows: Elasmobranchii 1, Chondrostei 2, Holostei 1, Teleosti 3, Crossop- terygii 1, Dipnoi 1, Urodela 3, Anura 1, Chelonia 1, Rhyncocephalia 1, Lacertilia 2, Crocodilia 1, Aves 1, Mammalia 7%. In each case special attention has been paid to the innervation of the muscles as a guide to homologies. By means of these data, and of the principles that became apparent as the work proceeded, reconstructions of the jaw musculature 62 ANNALS NEW YORK ACADEMY OF SCIENCES were attempted in the following series of extinct forms: Dinichthys (Arthrodira), Hryops (Temnospondyli), Labidosaurus (Cotylosauria), Tyrannosaurus (Theropoda), Cynognathus (Cynodontia). THE JAW MUSCLES IN RECENT VERTEBRATES PISCES ACANTHIAS Plate I, Figs. 1, 2 The elasmobranchs as primitive gnathostomes are far superior in rank to the pregnathostome stage represented by the ostracoderms, for the first two visceral arches have already taken their places as the future supports of the jaws and hyoid arch. For many geological ages the teeming multi- tudes of pregnathostomes no doubt tried to develop a perfected form of jaws, but up to the appearance of the elasmobranchs the attempts to de- _ velop something besides a suctorial mouth were hardly satisfactory. Somewhere in early Paleozoic times the vertebrates acquired the car- tilaginous jaws, for the acanthodians as far back as the upper Silurian had already developed the type of jaw that is to continue through the rest of the vertebrate series. The cartilages of the skull and body in the elasmobranch give a fairly firm and stable attachment for the muscles. The great advance has been in the change of function of the two anterior visceral arches. The first two arches of the visceral series have lost their function as supports for the gills, and form the cartilaginous structure that is to become the jaw and hyoid apparatus of the gnathostomes. The first arch has grown forward under the brain case and has attached itself to the ethmoid region at the anterior end and to the hyomandibular re- gion posteriorly. The palato-quadrate bar is continuous, forming a long bar extending from the anterior end to the posterior part of the side of the skull. The teeth have already developed in the sharks. The denticle-covered skin has been drawn into the mouth and by growing together or enlarg- ing the denticles have developed into fairly efficient teeth. The jaw system in the shark is just the opposite of that in Dinichthys. The maxillary region is securely fastened to the skull, although it may be movable, while the mandible is the movable agent with the articulation in the quadrate region of the palato-quadrate bar. This mandible in the shark is capable of movement only in one direction. There is no side movement in these forms as there is no muscular system to operate it. ADAMS, PHYLOGENY OF THE JAW MUSCLES 63 The adducting movement of the mandibles is accomplished by the great adductor muscles, while the opening of the jaw is left to the long muscles of the ventral region. The muscles of the elasmobranch head are very simple, showing traces of the segmental condition in many particulars and indicating the homology of the jaw muscles with the branchial muscles. They are attached to the cartilages and to the fascia of the skin, but the skin has not assumed the importance that it does in the higher forms where it has become ossified to form plates as in Amia. In the sharks the skin gives some support to the muscles but it is not of great importance. One of the first to work on the jaw musculature of the elasmobranchs? was Benjamin Vetter (1874). On page 406 he gives a system for the naming of the muscles of the head and branchial region that is still used, _ with some modifications, in the literature of the subject. He regards the adductor mandibule as part of the series of “adductores arcuum visce- ralium (Mittlere Beuger der Bogen)”; these are small muscles on the inner sides of the branchial arches stretched between the lower end of the upper middle segment and the upper end of the lower middle segment (p. 445). He divided the musculature as follows: Die muskulatur der Visceralbogen zerfallt nach Lage und Innerverirung in vier Gruppen oder Systemen: (1) Oberflichliche Ringmuskulatur, (2) Obere Zwischenbogenmuskeln, (3) Mittlere Beuger der Bogen, (4) Ventrale Lings- muskulatur. Vetter subdivides the muscles of the “Oberflachliche Ringmuskulatur” (Constrictor arcuum visceralium) as follows: Bei den Selachiern treten folgende Muskeln als gesonderte Differencirung dieses Systems auf: (1) M. constrictor superficialis, oberfliichlicher Con- strictor; (2) Mm. interbranchiales, Kiemenscheidewand Muskeln; (3) M. levator maxille sup., Heber des Oberkiefers; (4) M. trapezius, Heber und Vorwiirtszieher des Schultergiirtels. In the description of the jaw muscles of Acanthias the following muscles of the adductor or temporal group (innervated by V,) are con- sidered : | MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY V;,) Adductor mandibule (Adm.). Levator labialis superioris (L. 1. s.). Levator maxille superioris (L. m. s.). Constrictor superficialis dorsalis (C, s. d.). 2The authors followed and compared in the study of the elasmobranchs were: Vetter (1874), Tiesing (1895), Marion (1905) and Driiner (1903). 64 ANNALS NEW YORK ACADEMY OF SCIENCES MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Constrictor 2 superficialis dorsalis (C,md, Ruge; Csd,, ae Coracomandibularis (Co. m.). Coracohyoideus (Co. hy.). MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY V,) Adductor mandibule (Adm.).—This is the large adductor muscle of the shark which closes the mandible against the maxillary or palato- quadrate bar. It lies on the skull, anterior to the hyomandibular, and fills the lower part of the space between this and the eye. It arises along the dorsal margin of the quadrate. A superficial layer arises on the post- orbital process and some of the fibers come from the tendinous mass back of the eye. At the postero-ventral region a few of the fibers from C,sv join with the adductor. The insertion is on the cartilage of the mandible along the whole length of the exterior surface and slightly on the upper edge of the inner surface. A tendon extends to the levator labii superioris (L. 1. s.) somewhat as it does in the teleosts, where a tendon connects with the adductor from the premaxillary region of the skull. Marion (1905, p. 23) gives a similar muscle in Raia which he calls levator rostri. In Acanthias the adductor muscle is a large mass made up of fibers from several sources, as in the teleosts and ganoids. It is more divided and specialized in Raia than in the typical sharks. The typical condition of this muscle in the lowest forms shows fibers from several sources, and this is suggestive of the subdivisions of the mucle in the higher forms, where the same mass in the amphibians and reptiles is divided to a greater or less extent, according to the form of the animal and the type of jaws. Tiesing (1895, pp. 87-90) discusses the adductors of the various elasmo- branchs, showing this splitting of the muscle in some of them, especially Rhinobatus. Levator labit superioris (L. 1. s.) is a small muscle arising on the ven- tral portion of the skull, under the eyes and anterior to them, extending around the labial cartilages to meet and join with the adductor man- dibule. Vetter (1874, p. 406) calls it Add. 6 in Acanthwas and places it with the “Oberflachliche Ringmuskulatur”’ (Constrictor arcuum visceralium). Marion (1905, p. 21) follows Vetter and places it with the similar con- strictor, as a serial homologue’ of the M. levator maxille superioris. Tiesing (1895, p. 84) gives the origin in Mustelus “von vorderer Wand ADAMS, PHYLOGENY OF THE JAW MUSCLES 65 der Augenhohle unterhalb des Processus preorbitalis.”” Tiesing (Idem., p. 86) classes this muscle with the dorsal constrictors: “Mit der Erkennt- nis dass es sich um die Versorgung durch den Ramus III trigemni handelt, verliert auch der M. Levator labii superioris die ihm von fritheren Autoren zuerkannte selbstandigkeit und reiht sich dem system der levators resp. dorsalen Constrictors im Trigeminusgebiet an.” Levator maaiule superiors (L. m. s.).—This is one of the dorsal con- strictors which arises on the skull, just anterior to the constrictor super- ficialis dorsalis 1 (C,sd). It is inserted on the dorsal surface of the palato-quadrate bar. This muscle is so closely associated with C,sd in both origin and insertion that most writers have placed them together. Vetter (1874) places it with the dorsal constrictors and Marion (1905) follows his determination. Vetter (1874, p. 408) gives the function of the two muscles as follows: “Der Levator maxille superioris und C,sd heben den Oberkiefer, der erstere dreht ihn dabei um sein Gelenk mit dem Schadel nach vorn, der letzere nach hinten.” Constrictor (1) superficialis dorsalis (C,sd).—This small muscle is just posterior to the levator maxille superioris and is closely associated with it. Both muscles represent a division of one of the dorsal series as mentioned in the discussion of the other muscles. Its origin is on the wall of the skull above the spiracle, from where it curves around the anterior border of the spiracle to the insertion on the palato-quadrate bar, just posterior to the insertion of the levator maxille superioris. This constrictor represents the dorsal part of the original dorsal constrictor (C,sd) and in some pre-elasmobranch stage was probably much larger. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) There is no true depressor attached to the mandible in the elasmo- branchs that has any connection with the dorsal part of the skull. The depressing is performed by the long muscles of the hyoid region, assisted by the coraco-mandibularis and coraco-hyoideus. These are hyoid arch muscles and both are innervated by nerve VII as would be expected, as they belong to the region of the second suferficial constrictor. Constrictor (2) superficialis dorsalis (C,sd).—This is the large, undif- ferentiated constrictor that in the higher forms is to become the depressor mandibule of the Amphibia, birds and reptiles; but in the Pisces it is a wide muscle arising from the posterior part of the skull and from the fascia of the back muscles. It is inserted in the quadrate region of the upper jaw onto the cerato-hyal cartilage and onto the tendinous bridge of the dorsal and ventral constrictors. 66 ANNALS NEW YORK ACADEMY OF SCIENCES Coraco-mandibularis (Co. m.).—This les along the ventral medial line of the under part of the throat. It is an azygos muscle belonging to the long muscles of the ventral system. It arises on the fascia of the long muscles (coraco-arcuales), extends forward as the most superficial of the ventral muscles, and is inserted on the mandibular cartilage, near the symphysis. It is the true depressor muscle of the elasmobranchs and acts in depressing the jaw. Tiesing calls it a depressor, but it adds confusion to the nomenclature, and it should be regarded as a ventral muscle, used below the amphibians for this purpose. Coraco-hyoideus (Co. hy.).—This also assists in the depression of the mandible. While it is not.attached to the mandible, it is close to the coraco-mandibularis and assists in drawing down the mandible by pulling on the arch. It isa paired muscle, attached by fascia in its origin to the coraco-branchialis and coraco-arcualis communes. It is inserted on the underside of the hyoid arch near the median line. POLYODON Plate I, Fig. 4 The skull on the whole approaches the shark type. It consists largely of cartilage, the derm-bones being much reduced. The rostrum is enor- mously prolonged and flattened. The skull is extremely hyostylic, the long slender jaws being connected with the skull chiefly through the small symplectic and the long backwardly inclined hyomandibular. The mus- cles of the hyomandibular are large and well developed. As the fish feeds on small food particles, the jaws and their muscles are weak. ‘The adductor muscle arises on the palato-quadrate bar, and passes over a pulley-like groove at its posterior end and is inserted into the mandibular fossa. The jaw muscles of Polyodon, as described by Danforth (1913), resem- ble those of the sturgeon but are less reduced. ‘They are also fundamen- tally similar to those of the elasmobranchs. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY Y,) Adductor mandibule 1 (Ad. m.*, adm. of Danforth). Adductor mandibule 2 (Ad. m.?, adm.’ of Danforth). Protractor hyomandibularis (P. hy.). MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Retractor hyomandibularis et operculi (R. hy. et o.). ADAMS, PHYLOGENY OF THE JAW MUSCLES 67 MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY Y,) The adductor mandibule is divided into two parts: a large anterior portion, and a smaller deep part. The large portion extends anteriorly along the palato-quadrate bar, while the posterior, deep, portion is a short muscle from the quadrate region. Adductor mandwbule 1 (M. adm. of Danforth).—This is the larger section of the adductor which hes over the palato-quadrate bar, curves around the quadrate and is inserted in the suprameckelian fossa. Its origin starts on the dorsal, anterior end of the palato-quadrate and ex- tends backward, overlapped slightly along its ventral side by the maxilla; it curves downward under the maxilla at a sharp angle and is inserted ~ into the suprameckelian fossa and also on the dentary. Its curve is very abrupt, so that its insertion is at right angles to the main mass of the muscle. Adductor mandibule 2 (M. adm. of Danforth).—Just posterior to the abrupt curve of the adductor mandibule 1 arises the adductor man- dibule 2 on the posterior end of the palato-quadrate bar. It extends ventrally to be inserted on the dentary and in the suprameckelian fossa. Danforth (1913, p. 116) mentions some speculations in regard to the adductor mandibule 1 of Polyodon that are rather interesting and per- fectly justified from the conditions. He says: In Acipenser there is, in addition to the adductor mandibule, a strong con- strictor (Cs of Vetter) which overlies it. The latter arises from the antorbital process and extends around the lower jaw. The anterior part of the adductor in Polydon has a superficial resemblance to this muscle, but none of its fibers arise from any part of the cranium proper and I have been unable to find any indication that they ever pass over into the ventral constrictor, below the jaw. Consequently from the adult material alone, it cannot be stated with any cer- tainty that the anterior adductor of Polydon finds its homologue in the con- strictor of Acipenser, although there is a possibility that such is the case. From its position, it could be a part of the constrictor superficialis 1 of Vetter, as Danforth suggests. It is tempting to imagine that the old origin on the skull has been lost and that it slipped down to its present position. Several other forms have a muscle of this type and the embry- ology should show the truth or falsity of the assumption. This muscle protracts and closes the mouth. _ Protractor hyomandibularis (P. hy.).—This muscle strongly suggests the similar muscle in Acipenser. It is a double-headed muscle that arises from the base of the skull at the posterior end of the roof of the mouth and from the post-orbital process, anterior to the spiracle. It 68 ANNALS NHW YORK ACADEMY OF SCIENCES extends to the hyomandibular and is inserted along its anterior margin, with a long insertion extending almost to the distal end of the bone. It protracts the hyomandibular, pulling the distal end outwards and forward. The homology of this muscle is interesting. Danforth (1913) says: “The partial division of this muscle is of some interest, since the homologies of the levator arcuus palatini and the dilator operculi in the teleosts are rather uncertain.” MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Retractor hyomandibularis et opercult (levator and add. operculi?) » (R. hy. et o.).—This is a large sheet of muscle that arises along the groove in the cranium, under the long pterotic. It may represent the levator operculi and the adductor operculi of Amia. The fibers spread out and are divided into small bundles and are attached to the posterior edge of the hyomandibular. Posteriorly they attach themselves to the whole dorsal border of the degenerate operculum. A few superficial fibers extend over this sheet from the anterior part of the origin to the operculum. These muscles raise the hyomandibular and operculum. ACIPENSER Plate:!l, Wie. 3 The dermal plates of the skull are superficial ossifications. The carti- laginous skull of this form is more degenerate than in Polyodon, as the mouth is reduced to a small sucking disc, while Polyodon has duck-like jaws. The adductor is shrunken to a small, short muscle, as there is very little demand for a strong muscular action. The opercular and hyoman- dibular region have large muscles, as there is much movement in these parts during the ingestion of food. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) (1) Adductor mandibule (Ad. m.). (2) Protractor hyomandibule (P.h.). MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) (1) Retractor hyomandibularis (R. hy.). (2) Levator operculi (L. o.). ADAMS, PHYLOGENY OF THE JAW MUSCLES 69 MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY V,) Adductor mandibule (Ad.m.).—This is a small muscle that arises on the upper side of the palato-quadrate region. It curves around and is inserted on the small Meckelian cartilage. It raises the mandible and presses it against the marginal cartilages of the maxillary region. Protractor hyomandtbularis (P. h.).—This is a large muscle in the sturgeon. It arises in the post-orbital region, extends ventro-posteriorly and is inserted on the hyomandibular. It is concerned in the action of the gill apparatus and in the sucking action. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Retractor hyomandtbularis (R. h.).—It arises on the skull wall back of the spiracle and is inserted on the dorsal edge of the hyomandibular. It raises the gill apparatus. Levator opercult (li. 0.) (Vetter, 1874).—This arises along the side of the skull, just posterior to the origin of the retractor hyomandibularis. It is inserted on the operculum on the inner side. It pulls up the oper- culum. AMIA Plate II, Figs. 1, 2 In the very primitive skull of Amia, the chondrocranium is but little ossified and the dermal plates are still on the surface and very much of the primitive ganoid pattern. The hyomandibular and preopercular are sunken deeper into the skin, so that the adductor is of the teleost type, with its origin on the anterior face of the preopercular. The cartilagi- nous palato-quadrate and the Meckelian cartilage are incased in their dermal bones, and good teeth have developed, so there is need of good muscular development for the jaws. The quadrate, preoperculum and the cartilaginous skull make a good insertion for the splendid muscular system found in this group. The insinking of the preoperculum gives the adductor plenty of room for development and full advantage has been taken of this opportunity.’ MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY Y,) Levator maxille superioris (li. m.s.). This study on Amia follows the work of Allis (1897) and MeMurrich (1885). "0 ANNALS NEW YORK ACADEMY OF SCIENCES Levator arcus palatini (L. a. p.). Adductor mandibule (Ad. m.). Protractor hyomandibularis (P. h.). Dilator operculi (D. o.). MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Adductor hyomandibularis (Ad. h.). Adductor operculi (Ad. 0.). Levator operculi (L. 0.). MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Levator maxille supertoris (Li. m.s.).—This is derived from the mus- cle of the same name in the selachians. It arises on the hyomandibular and along the side of the cartilaginous part of the skull; part of it is anterior to the eyes. It is attached to the adductor muscle and to the dermis, between the maxilla and the palatine arch. Levator arcus palatim (L. a. p.).—Arises on the post-orbital process and is inserted on the metapterygoid and the hyomandibular. Adductor mandibule (Ad.m.).—There is a great change here from the condition of the selachians. The adductor mass is now attached to the bony elements of the mandible and is differentiated into three parts, the second of which is again divided into two. (a) Pars superficialis (Ad. m.*). (6) Pars temporalis lateralis (Ad. m.?). (c) Pars temporalis medialis (Ad. m.’). (d) Pars intramandibularis (Ad. m.*). (a) Pars superficialis (Ad. m.1, A? Allis) arises from the post-orbital process and the under surface and outer edge of the pterotic, and from the outer face of the preoperculum, hyomandibular, quadrate, and sym- plectic. It is inserted on the coronoid and extends into the supra- meckelian fossa. A tendon from this part extends to the inner side of the maxilla as in the selachians. This tendon represents a muscle of the selachians (levator labii superioris) that is lost in Ama, the tendon only remaining. (b) Pars temporalis lateralis (Ad. m.?, A*). The deep portion arises from the hyomandibular, quadrate, and the outer part of the metaptery- goid. It joins Ad. m.* near its insertion on the jaw. It is partly sub- divided into the two parts Ad. m.” and Ad. m.? ADAMS, PHYLOGENY OF THE JAW MUSCLES ‘il (c) Pars temporalis medialis (Ad. m.*) is the inner slip of the medial layer pars temporalis lateralis. (dq) Pars intramandibularis (Ad. m.*, A » Vetter) is the part of the adductor mass that extends forward into the hollow ramus of the jaw as in the teleosts. It arises from the fascia on the other two parts of the adductor and fills the hollow ramus, being attached to the splenial and the dentary. Protractor hyomandtbularis—This muscle is not present in Ama as a separate muscle, but its function is taken by the posterior part of the levator arcus palatini, this has a small insertion on the underside of the hyomandibular, thus acting as a protractor of that element. Dilator operculi (D.0.).—This arises on the pterotic, extends through the usual fossa in the hyomandibular and is inserted on the anterior, inner face of the operculum by a tendon. The path of this muscle over the hyomandibular, just above the preoperculum is well marked, as it is in all fishes. This muscle raises and pulls the opercular region outwards. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) These muscles of the facialis group represent the C,sd of Vetter, that is the dorsal part of the “second constrictor” pertaining to the hyoid arch (C,sd). Adductor hyomandibularis (Ad. h.).—This arises from the otic region and is inserted on the inner face of the hyomandibular, along the posterior edge to the articulation for the operculum. It pulls the hyomandibular dorsally. Adductor operculi (Ad. 0.). Levator opercult (L. 0.).—These two muscles of the operculum both arise on the pterotic and parietal, the adductor operculi being the anterior slip. They extend down to the operculum and spread out on its inner face. They raise the operculum. LEPIDOSTEUS Plate II, Fig. 3 Lepidosteus has a well developed skull with a great elongation of the mandible and maxille. The great forward prolongation of the quadrate and mandible gives what is demanded for a catcher of fish, namely, a quick snap. The enormous adductor with its temporal and masseter slips must serve to close the jaw with a very quick snap, so that the numerous sharp pointed teeth get a hold‘on the slippery prey. These yh) ANNALS NEW YORK ACADEMY OF SCIENCES muscles are inserted at a very oblique angle and the leverage is such as to give a very rapid movement with comparatively slight power. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Adductor mandibule (Ad.m.). (Divided into three parts.) Protractor hyomandibularis (P. h.). MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Adductor operculi (A. 0.). Levator operculi (L. 0.). MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY V,) Adductor mandibule (Ad.m.).—This muscle is divided into three parts: Adductor 1 (to preoperculum), adductor 2 (along the roof of the skull), adductor 3 (to quadrate). Adductor 1 takes its origin in a fan-shaped mass along the outer face of the operculum. It extends anteriorily, becoming tendinous at the posterior border of the eyes, and is inserted in the space above the Meckelian cartilage. Adductor 2 is a long muscle arising along the entire face of the cartilaginous region of the skull, from the preorbital region to the hyomandibular. It extends along the roof, dorsal to the eyes and to the anterior edge of the mandi- ble. The two pair almost meet in the median line, as only a thin ecarti- laginous plate separates them. It is inserted in the Meckelian fossa with the other parts of the adductor mass. Adductor 3 is a short por- tion of the adductor that arises on the tiny quadrate, spreads out in a thin sheet and is inserted on the coronoid process of the mandible. It is a very small muscle, lying under adductor 1. Protractor hyomandibularis——This muscle is between the dorsal and the ventral parts of the adductor mandibule. It arises on the orbito- sphenoid with a small tendon at its anterior end and a fleshy attach- ment to the side of the skull as it extends posteriorly to its insertion on the hyomandibular. It resembles a homologous muscle found in Acipenser, and Vetter calls it by the same name. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Adductor opercult (A. 0.).—This is a small muscle that arises on the hyomandibular and curves around to be inserted on the inner face of ADAMS, PHYLOGENY OF THE JAW MUSCLES "3 the operculum, near its anterior edge. It pulls the operculum forward .and is homologous with the muscle of the same name in Amia. Levator opercult (L. 0.).—This arises on the occipital region of the skull, spreads out in a fan-like insertion on the upper, inner face of the operculum. It raises the operculum. Both of these muscles are prob- ably the homologues of Csd, of Vetter and the C,md of Ruge. ESOX Plate III, Figs. 1, 2 In Hsox, as in other teleosts, the dermal bones have sunk into the skin so that the adductor region is free on the outside. The preoper- culum, metapterygoid, quadrate, and post-frontal regions give the ad- ductors a good surface for insertion. The teleost mandible becomes en- larged and the articulation with the quadrate is greatly improved in its mechanics. As the maxille are reduced and have lost the power to meet the mandibles, their teeth have disappeared and the mandibles are in- clined inwards to meet the teeth of the palatines. The following description is based partly on that by Vetter (1878) : MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YJ,) Adductor mandibule 4 (Add. of Vetter). Adductor mandibule 1 (Superficial). Adductor mandibule 2-+ 3 (To symplectic, etc. Deep.). Levator arcus palatini (Vetter). | MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Adductor hyomandibularis ( Vetter). Dilator operculi (Vetter). Levator operculi ( Vetter). Adductor operculi (Vetter). For homologies see Table I, p. 156. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) The muscles of Hsox have been worked out by Vetter (1878, p. 494). His names are used for the most part in the present description, although the nomenclature of the adductor mandibule is changed, as explained in the notes. The adductor has three distinct parts. v4. ANNALS NEW YORK ACADEMY OF SCIENCES Adductor mandibule 4 (Add. of Vetter, 1878, p. 494).—This large muscle mass fills the suprameckelian fossa and is attached to the side of the fossa and to the cartilage. It is homologous with that found in Amia (Ad. m.*) and in several other forms where the Meckelian fossa is large. Adductor mandibule 1 (Vetter, 1878, p. 494). —This is the outer sheet of the adductor, which completely covers the rest of the muscle. It takes its origin from the edge of the frontals, from the postorbitals to the articulation of the hyomandibular, along the face of the hyoman- dibular and the anterior face of the preoperculum; the lower part arises from the symplectic and the postero-ventral portion of the quadrate. It ends at the mandible with a short, wide tendon and joins with the rest of the adductor mass, to be inserted in the mandible, in the coro- noid region and in the suprameckelian fossa. Adductor mandibule 2—This is underneath the superficial adductor (Add. m.1). It arises on the metapterygoid, preoperculum, quadnate, and has a slight origin on the hyomandibular and operculum. This com- plex muscle becomes tendinous at the anterior end and extends to the jaw medial to the superficial adductor. It extends into the supra- meckelian fossa to join the rest of the adductor. Adductor mandibule 3.—The deepest portion of the adductor mass. Its tendon joins that of Ad. m.?. ) Levator arcus palatim (L.a.p.) (Vetter).—This is found along the upper part of the post-frontal region, after the adductor mandibule 1 is removed. It arises on the pterotic and alisphenoid and is inserted on the metapterygoid and hyomandibular. It pulls up on the palatine region and closes the gills. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Adductor hyomandtbularis (Ad. hy.) (Vetter, 1878, p. 502).—A small muscle between the hyomandibular and the skull that arises on the skull wall in the otic region and is inserted on the inner side of the hyoman- dibular. It adducts the hyomandibular, as its name indicates. Dilator opercult (D.0.).—This muscle is not to be seen until the adductor mandibule 1 is lifted off. It extends from the pterotic to the operculum. It arises on the pterotic and hyomandibular and extends over the hyomandibular and under the tip of the preoperculum to be inserted on the upper, inner face of the operculum. It opens the opercu- lar cavity. Levator opercult (l. 0.).—This muscle is just posterior to the dilator operculi. It arises on the posterior end of the pterotic with a slight ADAMS, PHYLOGENY OF THE JAW MUSCLES 5 ‘ attachment to the hyomandibular. It is inserted on the upper edge of the operculum where it spreads out in a fan-shaped mass. It raises the operculum. Adductor opercult (A. 0.).—This is a short muscle that arises on the posterior limb of the pterotic and in the epiotic groove. It is inserted under the levator operculi on its anterior edge and is also attached to the opercular process of the hyomandibular and to the origin of the adductor mandibule 2 (Vetter). It closes the operculum and pulls it dorsally. ANGUILLA Plate II, Figs. 4, 5 The peculiar reduction of the maxille and premaxille in the Apodes has made the mandibles incline inwards to meet the teeth on the palatines. The extreme is reached in the Murenide, where the maxille and pre- maxille are lost and the palatines and pterygoids assume their function. The eels have a reduced pterygoid region and the maxilla and premaxilla are small or lost, the vomers and palatines being supplied with teeth, and functioning as the maxillary elements. The mandible is changed in position so that it is inside of the palatines when it is closed. The muscular development of Anguilla is remarkably like that of cer- tain reptiles. ‘The dipnoans and Apodes are about the only examples among the fishes that show the adductor muscles extending up to the median line of the skull and meeting there, separated only by fascia. The condition in Apodes is unique in this respect, for the muscles are free to extend to the median line and have their movements entirely unhampered by any covering of bone. Thus the adductor muscle resem- bles the capiti-mandibularis of the reptiles and compares favorably with the temporalis muscle of some mammals in shape and development. AI- though the adductors meet on the median line their fibers do not mix, as they are separated by fascia. The hyomandibular is large and well muscled. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY Y,) Adductor mandibule. Dilator operculi. MUSCLES OF THE DEPRESSOR OR DIGASTRIO GROUP (INNERVATED BY VII) Levator operculi. "6 ANNALS NEW YORK ACADEMY OF SCIENCES MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY Y,) Adductor mandibule.—This muscle completely covers the skull pos- teriorly, covering the dorsal, median line to a depth of three or four milli- meters. It is in two layers, a superficial (Add. 1) and a deep (Add. 3). The superficial layer arises on the frontal, parietal, pterotic, and hyoman- dibular, and is inserted on the coronoid region of the mandible. The origin of this muscle is far different from that of the usual teleost muscle, which takes origin from the preoperculum. It has spread over the skull and arises much as in the reptiles. The great development of the hyo- mandibular and the reduction of the opercular bones is the probable cause of the change of origin. The deep layer (Add. 3) arises on the parasphenoid, sphenotic, hyo- mandibular, and quadrate. It joins the outer layer and is inserted on the mandible. Dilator operculi (D.0.).—This muscle is covered by the adductor. It arises on the sphenotic and hyomandibular and is inserted on the upper portion of the anterior border of the operculum. It raises the operculum and pulls it forward. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) ‘Levator opercult (lu. o.).—This arises on the posterior part of the pterotic and spreads out in a fan-shaped sheet on the outside of the oper- culum. It raises the operculum. This muscle is on the inside of the operculum in most teleosts but in the Apodes it creeps to the outside. The reduction of the opercular bones probably has something to do with this change. PALINURICHTHYS Plate III, Figs. 3, 4, 5 The skull is fundamentally similar to that of the perch but is short antero-posteriorly and with large orbits. The principal muscles of the jaws are as follows: MUSCLES OF THE ADDUOCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Adductor mandibule (1 and 2). Levator arcus palatini (L. a. p.). ADAMS, PHYLOGENY OF THE JAW MUSCLES vad Protractor hyomandibularis (P. h.). Dilator operculi (D. o.). MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Levator operculi (L. o.). MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) The adductor is divided into two layers and a third is present as the intramandibular slip. There is a connection by a rudimentary tendon with one of the anterior levator maxille muscles that arises at the anterior of the premaxilla and joins the adductor near its tendon. The main adductor arises along the anterior face of the preoperculum, following down along this bone to its tendon near the mandible. The deeper layer arises on the quadrate and metapterygoid region, joining the rest of the adductor and ending in a crescent-shaped tendon near the coronoid region of the mandible. This connects with the muscle in the mandible (Adm‘*) which is the Add.» of Vetter. This consists of a mass of fibers attached to the dentary, with all of the fibers converging to a central tendon, which is connected with the tendon of the main adductor. Levator arcus palatini (L. a. p.).—When the eye is removed this muscle is seen with its fibers extending ventrally to be attached to the palatines and pterygoids. It arises on the parasphenoid and most of the short fibers are inserted with a fleshy attachment to the palatine and a few to the pterygoids. It raises the palatine region. Protractor hyomandibularis (P. h.).—This muscle arises on the sphe- notic and extends under the dorsal end of the adductor, to be inserted on the outer face of the hyomandibular. It draws the hyomandibular and opercular apparatus forward. Dilator opercult (D. o.).—It arises on the sphenotic under the pro- tractor hyomandibularis and extends posteriorly to be inserted on the anterior, dorsal portion of the operculum. It pulls the operculum for- ward and raises it slightly. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Levator operculi (LL. o.).—It arises on the posterior end of the pterotic and extends downward to its insertion on the inside of the upper, inner face of the operculum. It raises the operculum and pulls it slightly forward. v8 ANNALS NEW YORK ACADEMY OF SCIENCES POLY PTERUS Plate IV, Figs. 1, 2 The condition of the skull in Polypterus is extremely primitive, as all the dermal elements are on the surface. The skull is broken up into small elements so that the comparison with the Devonian Rhipidistii, such as Osteolepis, is easily made. The elements may not be exactly the same, but they represent the breaking up of the hard dermal shell to allow the necessary movement occasioned by the muscular development. It might be possible to account for all of the breaks by making a phylo- genetic study of the muscles in the fossil forms. In this connection Gregory (1915, p. 327) offers the following very interesting and sug“ gestive hypothesis: It may be stated as a general hypothesis that in the dermocranium of the primitive fishes the position and arrangement of the sutures and the subse- quent pattern of the osseus elements are the evolutionary resultants of the various symmetrically balanced stresses induced by the action of the under- lying muscles of the eyes, jaws, branchial arches and pectoral limbs, in com- position with the position and size of the olfactory, optic and auditory cap- sules. It is at least a fact that sutures and articulations define loci of greatest mobility, centers of ossification define loci of least mobility. Differential growth of one region of the skull, as in the rapid elongation of the snout, also results in more or less rearrangement of the sutures and osseus elements. An examination of the skull of Polypterus shows that Dr. Gregory’s hypothesis works out well, as most of the breaks in the skull might be explained by the stress of the muscles actually present. The adductor mandibule would tend: to make the break over the frontal and parietal region, as this is at right angles to the pull. The pull of the masseter would cause the break in front of the preoperculum by its pull against the squamosal and quadrate elements. The spiracle and its muscle might account for the broken condition in that region with its many small plates. The breaks in the region in front of the orbits are more difficult to account for, but in the sharks and some of the other fishes there is a levator maxille which might have caused the breaking up in this region. The jaw muscles of Polypterus have been figured and described by Pollard (1892). MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Adductor mandibule (Ad. m.). Protractor hyomandibularis (P. h.). Levator maxille superioris (L. m. s.). ADAMS, PHYLOGENY OF THE JAW MUSCLES 79 MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Adductor hyomandibularis (Ad. h.). Adductor branchialis (Pollard). The differences in the musculature of the shark and of Polypterus are due to the fact that the latter has a bony skull roof and requires a differ- ent form of musculature. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV;,) Adductor mandibule.—This muscle is somewhat more complex than the adductor of the selachians, where the mass is rather compact. It may be divided into a temporal (Adm?’), masseter (Adm*) and pterygoid portions (Adm*). (a) The masseter (Adm*) is the largest part of the adductor and stretches across the face of the mass, so that the pull is almost along the line of the skull base. It is covered by the preopercular plate, so that it, as well as the rest of the adductor, is not seeu from the outside. The muscle slip arises along the back part of the skull where the preoperculum joins the hyomandibular and quadrate. These bones bound a triangular region at the posterior part of the skull where the masseter slip arises. It is attached to the preoperculum along the inner face, where it overlaps the hyomandibular and extends to the quadrate. The insertion is on the coro- noid process of the mandible. (b) The temporal portion (Adm?) of the adductor, as well as the pterygoid slip, are at right angles to the masseter portion, so that the combined pull of the three parts is at an angle of about 45° to the top of the skull as a base line. This slip arises on several bones of the dorsal part of the skull, on the postorbital and frontal. The attachment to the frontal (after Pollard, 1892, p. 391) is “to its under surface between its projecting edge and its articulation with the orbito-sphenoid, extending even above the eye.” ‘The insertion of the temporal portion is in the suprameckelian fossa. This part is anterior to the pterygoid slip and overlies it somewhat. It is at right angles to the masseter. (c) The pterygoid slip (Adm*) arises behind the temporal and be- neath it, on the orbitosphenoid and parasphenoid, and its insertion is on the mandible along with the temporal. This mass of muscle represents a part of the capiti-mandibularis of reptiles and the adductor of the selachians. Protractor hyomandibularis (P. h.).—T wo muscles connected with the adductor group assist in the movement of the operculum, the protractor 80 ANNALS NEW YORK ACADEMY OF SCIENCES hyomandibularis and the levator maxille superioris. They are closely associated with each other and by their retraction pull the operculum outward and help in moving the water in the gill chamber. . The pro- tractor arises on the postfrontal and is inserted on the operculum and hyomandibular where the two bones meet. A small slip of this muscle, according to Pollard, is attached to the bones around the spiracle and assist in regulating its closing and opening. Levator maxille superioris (Li. m. s.) Add. 8 Vetter—This muscle is closely connected with the protractor. It arises on the postfrontal and is attached to the metapterygoid and quadrate and to the lower edge of the hyomandibular. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Adductor hyomandibularis (Ad. h.).—This is the retractor hyoman- dibularis of Pollard. It arises in the otic region on the prootic and along the ridge of the postero-external process. The anterior part of the muscle is called the retractor. The insertion is on the hyomandibular, above the posterior articulation of this bone with the operculum. It is attached to the anterior part of this articulation and on the inner side of the bone. Adductor branchialis (Ad. br.) (Pollard).—There is a small muscle at the angle of the jaw that, according to Pollard (1892, p. 389), may represent the adductor arcus branchialis of the selachians. It is in the ligaments that connect the hyomandibular, quadrate and stylohyal. NEOCERATODUS Plate IV, Figs. 3, 4 The wide massive skull of Ceratodus (Neoceratodus) is correlated with the peculiar development of the splenial, vomerine and palatine teeth. The cartilaginous skull is covered by the superficial derm bones and with a great space reserved at the posterior region for the accommodation of the large adductor mandibule. The opercular region is reduced and the hyomandibular is vestigial or absent. Gtnther (1871, p. 524) saw this little vestige of both the hyomandibular and the symplectic but did not recognize them as such. Huxley (1876, pp. 3-4) says: It is obvious that this little cartilage is the homologue of the hyomandibular element of the hyoidean arch of other fishes, the small conical process being the rudimentary symplectic, and, therefore, that it is itself the dorsal element of the hyotdean arch, attached in its normal position, as its relations to the seventh nerve show. (Huxley’s observation on Giinther’s work. Giinther, 1871, p. 524.) ADAMS, PHYLOGENY OF THE JAW MUSCLES 81 This small cartilage, then, represents the hyomandibular and the sym- plectic of the teleosts. It is in the correct position for these bones and there is little doubt of the homology. With its reduction there has been quite a change in the opercular region, as the opercular bones are reduced and changed together with the preopercular. Gtmnther thought that a small bit of cartilage on the anterior edge of the opercular was the vestige of the preoperculum. Goodrich (1909, pp. 237-238) says: It is in the connection of the skull with the visceral arches that the dipnoi have diverged most conspicuously from the other fishes. The modern genera are completely autostylic. The pterygo-quadrate bar is firmly fused to the eranium in front and behind. The spiracle disappears and the hyoid arch is well developed, with a medial basihyal, paired hypohyals and large ossified ceratohyals. But the hyomandibular takes no share in the support of the jaws. It disappears, indeed, entirely in the Dipneumones where the cerato- hyals alone remain, and, as Huxley showed, is represented in Ceratodus by a minute vestigial cartilage, overlying the hyomandibular branch of the seventh nerve. The skull of Ceratodus has a continuous dermal temporal roof as in the stegocephalians. Parts of the skull resemble the cartilaginous struc- ture in the urodele embryo, especially in the region of the arches, but here the re- semblance stops. In the arrangement of the jaw muscles this dipnoan is very simple. The skull con- sists of a massive cartilag- Figure 1 inous part with a covering Mandible of Neoceratodus forsteri with the tendi- nous fascia of the adductor mandibule muscle of dermal bones which gives the head its large size. The space between the cartilage surrounding the brain and the dermal bone is filled with the enormous temporal muscle which supplies the motive power for the great crushing apparatus. ‘The general aspect of the head is amphibian-like to an extent found in no other fish but the eels. There is a space along the mid-dorsal region of the cartilaginous skull that is covered with the temporal muscle and with the muscles of the neck region. In Polypterus and Amia the muscles of the skull top make no approach to this extension in the dorsal region, but in the eels the temporal muscles extend up and the muscles of the two sides meet in a reptilian way. The musculature of Neoceratodus, in fact, represents a highly specialized dipnoan type, retaining very little of the primitive fish type. The loss of the hyomandibular causes the loss of several muscles common to the elasmobranchs and the teleosts. 82 ANNALS NEW YORK ACADEMY OF SCIENCES MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY V,) Adductor mandibule (Ad. m.). MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Levator operculi (L. o.). MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Adductor mandibule.—The adductor muscles of Neoceratodus are the largest found in fishes. The adductor is divided into two slips—a mas- seter (Adm*) and a temporal (Adm?)—which give the cutting and crushing power to the powerful dental plates. (a) The masseter slip (Adm.*) is quite small and much shorter than the temporal portion of the adductor. It arises in the quadrate region and extends forward to be inserted behind and below the insertion of the rest of the adductor. It also has a small tendinous sheet, but it is small in comparison with the sheet of the main adductor. (b) The temporal slip (Adm?) is the larger of the two muscles. It arises along the cartilaginous brain case, extending from a point anterior to the eyes to the posterior part of the brain capsule and extending well down on the sides. It is also attached to the bones of the roof of the skull, where they cover it. In dissection the muscle is seen to be broken up into small bundles that are attached to the side walls of the skull. In the median line the cartilaginous skull does not extend to the roof of the skull in the region of the adductor muscles, so that the muscles fill this gap. They nearly meet in the midline, being separated only by some tendons of the long neck muscles and by fascia. This part of the ad- ductor is divided by a great tendinous sheet to which the fibers from both sides join. It is very heavy and thick, thus giving great power. It is inserted on the coronoid region in the Meckelian cartilage region. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Levator operculi.—The levator is the only other muscle in the upper. part of the skull. It arises on the posterior face of the lower part of the cartilaginous capsule and is inserted on the inner side of the opercular region. The mandibles are depressed by the long ventral muscles that are at- tached to the mandibles close to the symphysis and by the hyoid muscles. ADAMS, PHYLOGENY OF THE JAW MUSCLES 83 The loss of the hyomandibular and the degeneration of the opercular bones has caused the loss of the usual muscles of this region of teleosts. AMPHIBIA RANA Plate V,. Figs. 1; 2 The fundamental resemblance in the skull of Anura to some of the fossil Amphibia, for example, such as Cacops and Eryops, is quite strik- ing. These are indeed so much like the Anura that in studying them for restoration of the muscles it was found that the musculature demanded ‘was invariably of the anuran type. Cacops in side view shows a type of covered skull that has opened eut to a certain extent in the temporal region, while remaining solid in the dorsal region. Some of the modern Anura, 1. e., Pipa americana, show something of the covered condition found in the stegocephalians, giving some likenesses to these fossil forms, although this resemblance may well be secondary. LHryops, also, is very much like the Anura in the palatal region, although the dorsal part of the skull appears to be quite different, because of the complete covering of dermal bones which it has retained from its early fish ancestors. The frog skull represents a fenestrated condition of the roofed skull, with.the palatal, postorbital and temporal region cleared of their bony covering. There is a hght musculature in the jaw region to meet the conditions of the weak mandibles. It has been suggested (Gregory, 1917) that this similarity of the Anura and the stegocephalians is more genetic than convergent and that our Anura may indeed represent certain remnants of stegocephalians in which the roof of the skull became fenes- trated. The jaw muscles in the frog, on account of the great open palatal region, are all on the posterior part of the skull, as there is no place for the muscles at the front part of the skull. The jaw muscles of the Anura are given the mammalian names by Ecker and Wiedersheim (1896-1904, pp. 133-136). MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Capiti-mandibularis superficialis. (a) Pars major (Masseter major of EK. and W.). (b) Pars minor (Masseter minor of E. and W.). Capiti-mandibularis profundus (Pterygoideus of E. and W.). Pterygoideus anterior (Temporalis of E. and W.). 34 ANNALS NEW YORK ACADEMY OF SCIENCES MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP ji (INNERVATED BY VII) Depressor mandibule (I. and W.). MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YJV,) Capiti-mandibularis superficialis—This muscle is divided into two parts by Ecker and Wiedersheim and called by them masseter major and masseter minor. It seems to be a muscle representing the superficial part of the capiti-mandibularis mass and may represent the two portions, as it is divided in the reptiles in this paper. (a) Pars major.—This arises by two heads, one from the ona process of the squamosal and the other from the lower quadrant of the tympanic annulus. It is inserted on the upper edge and outer side of the mandible and serves to tighten the ear-drum, thus acting as a tensor tympani. (b) Pars minor. ae is smaller than the major and noe to it. It is double-headed also, arising from the anterior border of the posterior arm of the squamosal and from the lateral knob of the quadratojugal. It is inserted on the mandible, posterior to the major. It is much shorter than the major. 3 Capiti-mandtbularis profundus (Pterygoideus of EK. and W.).—This is posterior to the eye and is covered by the pterygoideus anterior (tem- poralis of E. and W.). It originates on the fronto-parietal and prodtic and is inserted on the coronoid process, just posterior to the insertion of the pterygoideus anterior (‘Temporalis). Pterygoideus anterior (Temporal of E. and W.).—This is a large muscle that fills most of the space between the prodtic and the eyes. It curves around the annulus of the ear, covering the capiti-mandibularis profundus and going under the pars major of the capiti-mandibularis superficialis. It is a double-headed muscle, one head arising on the ridge between the proodtic and the fronto-parietal, while the second head, aris- ing on the anterior edge of the posterior limb of the squamosal, joins the first and is inserted on the coronoid process of the mandible. I call it pterygoideus anterior because it appears to be homologous with a muscle of the same name in the Reptilia. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule (Ecker and Wiedersheim).—The depressor of the jaw is a large muscle that covers the posterior part of the skull, overlap- ADAMS, PHYLOGENY OF THE JAW MUSCLES > 26 ping the other muscles of that region. It is double-headed, arising on the posterior upper limb of the squamosal and from the lower part of the annulus tympanicus and from the dorsal fascia. The anterior head arises on the posterior limb of the squamosal and from the lower part of the tympanic annulus. It joins with the posterior portion and is inserted on the angular. The head that arises on the dorsal fascia springs from the region of the upper part of the scapula and extends down to join the anterior or cephalic portion of the muscle. The anterior head tightens the ear-drum and lowers the jaw. CRYPTOBRANCHUS Plate V, Figs. 3, 4 ~The skull of Cryptobranchus (using this name in a broad sense to include the American and Japanese forms) is much depressed and widened. The squamosal is far up on the skull, making a shoulder and groove around which the temporal muscles ride, so that their path is well fixed. The pterygoids are flattened out to fill the region posterior to the palate and to supply good origins for the muscles. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Capiti-mandibularis superficialis (C. m.s.). == Masseter (Osawa). = Petro-tympanicus (Hoffmann). -Capiti-mandibularis profundus (C. m. p.). = “Temporalis” (Osawa). Pterygoideus posterior. = Pterygoideus (Hoffmann and Osawa). Pterygoideus anterior. = Temporalis of Osawa. = Fronto-parieto-maxillaris of Hoffmann. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule (D. m.*, D. m.?). = Digastric of Humphrey. = Cephalo-dorso-maxillaris of Hoffmann. 86 ANNALS NEW YORK ACADEMY OF SCIENCES MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY V,) Capiti-mandibularis superficialis (C.m.s.)—This muscle covers the lower part of the temporal muscles. Its fibers extend posteriorly as they do in most urodeles. It arises on the whole outer face of the squamosal and extends over the pterygoid bone to be inserted on the posterior half of the exterior face of the mandible. Capiti-mandibularis profundus (C.m.p.).—This is the posterior slip of the muscle called “temporal” by Osawa. It is a thin muscle that arises on the third neck vertebra, extends forward to join the pterygoideus anterior and is inserted on the inner side of the mandible. Pterygoideus postertor.—Very small in this form. Pterygowideus anterior (Pt. a.).—This is the anterior part of the tempo- ral muscle of Osawa. It arises on the pre-frontal and fronto-parietal, extends under the eye and converges rapidly to a narrow tendon, and is inserted on the coronoid process and in the fossa. This muscle is a part of the muscle usually called a temporal muscle, but it is considered as the homologue of the muscle found in the reptiles called pterygoideus anterior in this paper. i MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule (D.m.*, D. m.?).—This is a double-headed mus- cle, as it is in all of the amphibians. It arises on the dorsal and posterior part of the squamosal, with a second part arising from the dorsal fascia. The anterior part arises from the otic region and from the posterior, upper face of the squamosal. Both parts are inserted on the upper and outer face of the angular bone of the mandible. AMPHIUMA Plate V, Fig. 5 The skull is elongated and there is a prominent sagittal crest so that a deep fossa is formed for the muscles of the upper part of the skull. The skull roof is open so that the muscles have free play, as in most urodeles. The pulley arrangement of the dorsal muscles gives a very definite action to the jaws and is probably correlated with the backward extension of the capiti-mandibularis profundus, which is attached to the vertebre of the neck. ADAMS, PHYLOGENY OF THE JAW MUSCLES 87 MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Capiti-mandibularis superficialis. = Masseter. == Petro-tympano-maxillaris of Hoffmann. Capiti-mandibularis profundus. == Posterior head of the temporal of others. = Fronto-parietal maxillaris (Post part) of Hoffmann. Pterygoideus posterior. = Pterygoideus. = Pterygo-maxillaris of Hoffmann. Pterygoideus anterior. = Anterior slip of the temporal of others. = Anterior part Fronto-parieto-maxillaris of Hoffmann. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YJ,) Capiti-mandibularis superficialis (C.m. s.).—This is the outer or mas- seteric slip of the temporal mass, which covers over the other temporal muscles. It has a double head; the anterior arising on the large, outer face of the squamosal, while the posterior head arises on the ventral part of the same face. It is inserted on the outer face of the mandible on the posterior half. Capti-mandibularis profundus (C.m. p.).—This posterior part of the temporal mass arises from the fourth cervical vertebra, extends around over the groove on the skull, and, becoming tendinous, joins with the anterior part of the muscle called pterygoideus anterior in this paper. It is inserted on the coronoid region and in the fossa. Pterygoideus posterior (Pt. p.).—This is a large muscle in Amphiuma, arising on the pterygoid under the capiti-mandibularis superficialis. It is inserted on the coronoid process, posterior to the insertion of the other temporal muscles. Pterygoideus anterior (Pt. a.).—This is the anterior part of the muscle usually called the temporal. It arises along the groove on the fronto- parietal and from the orbito-sphenoid. It extends downward, rapidly converging, joins with the capiti-mandibularis profundus, and is inserted in the coronoid region of the mandible. 88 ANNALS NEW YORK ACADEMY OF SCIENCES MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule (D.m.).—This is a double-headed muscle, as in most urodeles. The anterior portion arises on the posterior face of the squamosal, the posterior from the dorsal fascia. They are inserted on the outer, dorsal face of the posterior end of the mandible. AMBLYSTOMA Plate V, Figs. 6, 7 The remaining urodeles are very similar in musculature, at least in. the three forms studied in this paper. About the only difference is the separa- tion of the lower, inner part of the temporal mass to form a separate pterygoideus posterior. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY V,) Capiti-mandibularis superficialis (C. m.s.). = Masseter. Capiti-mandibularis profundus (C. m. p.). = Posterior slip of the temporal. Pterygoideus posterior (Pt. p.). = Pterygoideus. Pterygoideus anterior (Pt.a.). == Anterior head of the temporal. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibularis (D. m.). REPTILIA CHELYDRA Plate V1, Figs. 1, 2 The primitive chelonian Proganochelys is the earliest known representa- tive of the Chelonia. Unfortunately it is known only: by the cast of the interior of the shell. Although the skull is unknown it was probably of the heavily roofed type, something like that of the existing Chelone. Watson (1914, pp: 1011-1020) describes the Permian genus Hunotosaurus as a probable ancestor of the Chelonia. It is quite probable that the ancestral chelonians were like the cotylosaurs with the temporal region ADAMS, PHYLOGENY OF THE JAW MUSCLES 89 of the skull covered and that there never has been a representative of this group with any fenestration of the lizard type. They have adopted a different scheme for the opening of the temporal muscle region by the posterior excision of the temporal roof, leaving the muscles of the head more or less bare. Except posteriorly, the roof is complete in Chelone and. there is a progressive reduction of the roof in the modern forms through Chelydra and Trionyx, until finally the opening is complete in Oistudo, where even the jugal has lost its. hold on the quadrate. These forms thus give a morphological series. The reduction of the temporal roof is analogous to the fenestration of the skull in other orders of rep- tiles, where the temporal roof is perforated dorsally and laterally. The great occipital crest indicates a corresponding temporal muscle in Chelonia, where the muscle extends behind the condyle and back over the vertebree of the neck. The quick snap of the jaws of Chelydra and Trionyx is due to the extension of the occipital crest which gives the temporal muscle a long origin and an oblique angle of insertion. The great separation of the squamosal from the parietal causes the depressor mandibule to slip down from its usual origin on the parietal to the out- wardly projecting squamosal. The turtle with its monimostylic skull has very simple jaw muscles, only three muscles being differentiated. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Capiti-mandibularis (C. m.). = M. Occipito-squamoso-maxillaris, Hoffmann (1890). == Schlafenmuskeln, Wiedemann. = Temporalis, Bojanus, Stannius, Cuvier, Owen. Pterygoideus anterior (Pt. a.). = Pterygo-maxillaris, Hoffmann. = M. Pterygoideus, Bojanus, Owen. = Fligelmuskel, Wiedemann. = Pterygoideus internus, Stannius. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP ’ (INNERVATED BY VII) _ Depressor mandibulz (D.m.). _ == Digastricus maxille, Bojanus. == Squamoso-maxillaris, Hoffmann. == Masseter (apertor oris), Wiedemann. = Apertor oris, Owen. | = Senker des unterkiefers, Stannius. 90 ANNALS NEW YORK ACADEMY OF SCIENCES MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YJ,) Capmti-mandibularis (C.m.).—This represents the large capiti-man- dibularis of the other reptiles and the adductor mandibularis of fishes, or at least a part of it. It is peculiar in the turtles in that they have developed a great occipital spine that supports this muscle. It arises on the following bones: prootic, quadrate, parietal, squamosal, occipital spine, opisthotic. It is inserted on the posterior part of the mandible. — Pterygoideus anterior (Pt. a.).—This is the large pterygoid muscle of reptiles with a monimostylic skull. It covers the floor of the pterygoid and palatine region and has a firm hold on the edge of the palatal vacui- ties. It arises on the pterygoids and palatines, extending almost under the eyes, from the parietal, pterygoid, prodtic and quadrate. It is in- serted on the inner face of the prearticular. It does not wrap around the mandible on the outside as it does in most reptiles. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule (D.m.)—The backward growth of the squa- mosal has captured this muscle so that it now is attached to it, instead of to the parietal, as in most reptiles. In Chelydra the whole origin is on the large and prominent squamosal, which may be explained by the assumption that the growth of the squamosal pushed back on the depressor mandibule (parieto-mandibularis), and that, gradually, the attachment on the squamosal became more important, and finally the origin on the parietal was lost, as a result of the shifting of the bones of the skull. The depressor mandibule is attached along the upper, posterior face of the squamosal and is inserted on the under surface of the articular. — There is much in the condition of the skull in turtles to suggest the cotylosaurs, and I assume that the muscular system must have been similar. : SPHENODON Plate VI, Figs. 3, 4 The supratemporal fenestra of Sphenodon gives exit to the temporal portion of the capiti-mandibularis on top of the skull, while the lateral temporal fenestra permits the masseter portion to expand freely in masti- cation. Owing to the fixed or monimostylic condition of the quadrate, there is very little movement either of the fore part of the skull upon the back part or of the pterygoid region. In correlation with this immobility the specialized pterygoid muscles are absent. ADAMS, PHYLOGENY OF THE JAW MUSCLES 91 The jaw muscles of Sphenodon are slightly more subdivided than those of Chelydra, in correlation with the more open construction of the skull. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YJ;) Capiti-mandibularis. (a) Capiti-mandibularis supaemane (GC. mar 8). <= Outer fibers of Osawa’s temporal. (b) Capiti-mandibularis medius (C. m. m.). = Temporalis, Osawa (superficialis). (c) Capiti-mandibularis profundus (C. m. p.). = Pterygoideus externus, Osawa. Pterygoideus anterior (Pt. a.). MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule (D. m.). == Parieto-mandibularis, Osawa. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY V,) Capiti-mandibularis—This muscle is the large muscle mass of the rep- tiles and it is taken to represent the mother mass of several muscles, as is mentioned elsewhere in this paper. It seems to be the conjoined masseter and temporal fibers, so that the divisions of the muscle are given the names used below. (a) Capiti-mandibularis superficialis (C. m. s.).—This part of the temporal mass consists of the fibers that always extend over the deeper fibers in the reptiles. (b) Capiti-mandibularis medius (C. m. m.).—This is the inner part of the main mass, or the temporal of Osawa. The capiti-mandibularis mass arises in the temporal fossa on‘the parietal, squamosal, quadrate, the inner side of the jugal and from the temporal fascia. It is inserted on the point of the coronoid and on the inside and outside of the posterior third of the mandible. (c) Capiti-mandibularis profundus (C. m. p.).—This deeper section of the temporal mass is separated in this form from the rest of the tem- poral mass. It arises on the parietal, postfrontal, prodtic, epipterygoid, the membrane between epipterygoid and the prootic and from the outer face of the pterygoid. 92 ANNALS NEW YORK ACADEMY OF SCIENCES Pterygoideus anterior (Pt. a.).—This short, strong muscle arises on the ventral border and inner side of the quadrate, from the inter-orbital floor, pterygoid and transverse. It has the typical reptilian insertion of this muscle, wrapping around the posterior end of the articular. It is inserted on the medial face and ventral border of the posterior fifth of the mandible. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule (D. m.).—This muscle, the homologue of the depressor of other animals, is called parieto-mandibularis by Osawa. It is a large muscle which arises from the posterior border of. the parietal, from the ligamentum nuche, and to a slight extent from the squamosal. It is inserted on the posterior face of the articular or on its retroarticular process. ALLIGATOR Plate VI, Figs. 5, 6 In the alligator skull there is a great reduction of the posterior region and a corresponding elongation of the antorbital region. The palate is closed by the approximation of the secondary shelves of the maxille, pala- tines and pterygoids, so that the condition partly resembles that of the mammals. ‘The pterygoids are also very closely appressed, so that the posterior internal nares are forced far to the rear and are almost ventral to the articulation of the mandible with the quadrate. There has been a progressive reduction of the temporal fenestree, so that the heavily roofed skull of the alligator represents the specialized modern form of an ancient order that had a much more open skull with large fenestree and very different proportions of the skull. The supratemporal fossa has been reduced until it is almost rudimentary, while the rest of the posterior region has also been encroached upon until the muscle space is quite small. The quadrate has shifted its position by inclining posteriorly, giving the animals a much larger gape; the quadrate is fixed or moni- mostylic. The auditory region is much changed by the secondary clos- ing of the otic notch, so that the meatus appears to be in a different posi- tion ; but this condition is merely the result of the closing in of the notch, so that its original position is masked. .The small size of the posterior region of the skull and the corresponding reduction of the capiti-man- dibularis is in a way compensated for by the great development of the pterygoideus anterior muscle which has extended over the floor of the ADAMS, PHYLOGENY OF THE JAW MUSCLES 93 palate and into the maxille. This muscle has an important part in the closing of the long mandibles. The jaw muscles of the alligator are of the io found in monimostylic reptiles. The fixed pterygoids and palatines demand no muscles for their movement and: consequently the muscles that function in Varanus and other streptostylic forms are not differentiated. 'The muscles of the capiti-mandibularis are pinched up, especially in the temporal section, as the temporal fossa is much reduced in most modern Crocodilia. This reduction is secondary, for the early fossil forms show no such reduction, but rather the opposite condition, with large supratemporal and latero- temporal fenestre and small orbits. Most of the Mesosuchia show a large supratemporal fenestra as in Teleosawrus, where the fenestre are of large size. There is a progressive closing of this fenestra from Teleo- saurus of the Jura through Geosauwrus, Goniopholis and Tomistoma. This closing and the pinching in of the temporal region means that the outer, or masseter, slip of the capiti-mandibularis (capiti-mandibularis superficialis) is enlarging and is taking over the principal work of closing the jaws, while the temporal slip is being progressively reduced. 'The pterygoid muscle is peculiar in that its anterior portion (pterygoideus anterior) has dug its way under the eye and into the maxilla, extending to a point far anterior to the eye, since it lies on the palatine and pene- trates far into the maxilla. The depressing of the jaw is done by the usual muscle, the depressor mandibule. The Crocodilia spend much of their time lying on the mud, and the action of the depressor in this posi- tion is to raise the head if the mandible is resting on something fairly firm. The Crocodilia have some peculiar external ear muscles, necessary in the crocodile from the advanced condition of the ear with its external flap. The nerves divide the muscles into two groups. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY Y,) Capiti-mandibularis. (a) Capiti-mandibularis superficialis. = Masseter portion. (b) Capiti-mandibularis medius. = Temporal slip. (c) Capiti-mandibularis profundus. == Deep part of temporal mass. Pterygoideus anterior. | = Pterygo-mandibularis, Bradley. Pterygoideus posterior, Lubosch. 94 ANNALS NEW YORK ACADEMY OF SCIENCES MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) — Depressor mandibule. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY.V,) Capiti-mandrbularis. (a) Capiti-mandibularis superficialis (C. m. s.).—This is the outer slip of the temporal mass, which does most of the work in the closing of the jaw. It arises on the parietal, squamosal, quadrate and quadrato- jugal and is inserted in the suprameckelian fossa, extending forward into the dentary. It fills the region of the skull behind the pterygoids. The large external fenestra of the mandible gives the muscle room for expan- sion. ‘The superficial layer (masseter) is subdivided into several i one being attached to the surangular. (b) Capiti-mandibularis mediws (C. m. m.).—This is the smaller of the slips of the mass. It extends down on the inner side of the capiti- mandibularis mass, arising on the bones surrounding the supratemporal fossa, into which it extends. It arises on the parietal, squamosal and postfrontal. Its insertion is on the coronoid, where it curves around the anterior edge of the capiti-mandibularis superficialis and extends under this slip to the mandible. The mandibular nerve separates it from the superficial slip. A small capiti-mandibularis profundus (pterygoideus post. Lubosch) attaches to the tendon of this muscle. Lubosch (1914, p. 699) says: Sehen wir vom Masseter und Pterygoideus anterior ab, so inseriert der sehr schwache, zweischichtige Temporalis mit einer kraftigen kurzen Sehne am Com- plementare. Ein Teil der Fasern endet an einer knorpelharten Zwischensehne. Von dieser Zwischensehne entspringen fraglichen Muskelportionen, welche ihrerseits zum Pterygoideus posterior gehoéren. (c) Capiti-mandibularis profundus (C. m. p.).—This small muscle which joins the temporal mass is given this name, as it is assumed to belong to the inner layer of the temporal mass. Pterygoideus anterior—This anterior slip arises on the palatine, maxilla, pterygoid and transverse (ectopterygoid), extending over the floor formed by these bones and digging into the maxille. It extends inward to the limits of the narial passage. This muscle is the same as the great pterygoid muscle in Chelydra and is typical of the monimostylic reptiles. In the crocodile, however, it has a much greater forward ex- tension. ADAMS, PHYLOGENY OF THE JAW MUSCLES 95 Pterygoideus postertor.—This muscle (called pterygoideus posterior by Lubosch, who also includes a small slip that joins the capiti-mandibu- laris), arises on the quadratojugal and quadrate and joins with the an- terior slip to be inserted on the mandible. A small slip from this joins the temporal mass and is designated as the profundus in this paper. These pterygoid muscles wrap around the posterior end of the mandible, where they swell out, making a large mass on the postero-ventral side of the jaw. This enlargement of the muscle at its insertion is paralleled in Cryptobranchus, as observed by Lubosch (1914, p. 698), who says: “Der Pterygoideus, zerfallt seiner Innervation nach wiederum in zwei Kom- plexe, der Pterygoideus anterior und der Pterygoideus posterior, worin Ubereinstimmung mit Verhialtnissen der Urodelen besteht.” MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule.—This is the typical depressor of the reptiles, arising on the parietal, squamosal and exoccipital. It is firmly inserted on the posterior prolongation of the articular. IGUANA Plate VII, Figs. 1, 2 The skull of Iguana is of the streptostylic type, although it is quite solidly constructed and much less specialized than that of Varanus. There is very little movement in the quadrate and pterygoid region, so that the muscles that move these parts in Varanus are not differentiated. The rest of the jaw musculature is very similar to that of Varanus, which is more fully described under its section in this paper. The fenestration in the temporal region of the skull of Iguana is similar to that of Varanus, with a large supratemporal fenestra and with a large sinus below the postorbital and squamosal, this giving the muscles plenty of room to expand. The skull has accommodated itself to the muscles in several ways. The supratemporal fenestra is large and the parietal has expanded dorsally and posteriorly to make a large origin for the capiti-mandibu- laris. . MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY V,) Capiti-mandibularis. (a) Capiti-mandibularis superficialis. == Masseter slip. 96 ANNALS NEW YORK ACADEMY OF SCIENCES (6) Capiti-mandibularis medius. | = Temporalis. (c) Capiti-mandibularis profundus. == External pterygoid of Mivart. —= Pterygoideus externus, Hoffmann. = Pterygo-mandibularis, Hoffmann. = Internal pterygoid, Sanders. = Entopterygoid, Sanders. —= Pterygoidien externe, Cuvier, Duméril. Pterygoideus anterior. ry == Pterygoidien interne, Cuvier, Stannius. — Pterygoideus internus, Hoffmann. == Internal pterygoid, Mivart, Edgeworth. —= External pterygoid, Sanders. = Ectopterygoid, Sanders. —= Pterygo-mandibularis, Bradley, Watkinson. — Pterygoideus, Versluys. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY Y;) Capiti-mandibularis—This is the large temporal muscle which is divided into three slips in this paper. (a) Capiti-mandibularis superficialis (C. m. s.).—This masseter slip is lower down on the outside of the mass. It arises on the quadrate, squa- mosal and quadratojugal. Its fibers extend over the fibers of the temporal slip and blend with them to be inserted on the coronoid and the dorsal edge of the mandible. They extend down on the outer face to quite an extent, which is not common in the reptiles, as usually the insertion is entirely on the inner side of the mandible. They also extend down on the inner side. This crossing of the temporal and the masseter slips gives two pulls to the mandible, a straight dorsal and a posterior one. (b) Capiti-mandibularis medius (C. m. m.).—The temporal or median slip fills the temporal fossa; 1t arises on the parietal, postfrontal and squamosal. The supratemporal fossa is large and the parietal is extended out, so as to furnish a large insertion for this part of the muscle. It ex- tends down between the masseter and the inner slip to be inserted 6n the mandible. ADAMS, PHYLOGENY OF THE JAW MUSCLES 97 (c) Capiti-mandtbularis profundus (C. m. p.).—This muscle is the homologue of the muscle of the same name in Varanus and is strongly developed in reptiles with a columella cranii (epipterygoid). It arises on the outer face of the epipterygoid and on the outer face of the ptery- goid, extends ventrally, and is inserted on the mandible on the lower part of the posterior inner face of the mandible. Pterygovdeus anterior (Pt. a.)—This arises on the pterygoid and wraps around the end of the mandible. The origin is on the under side of the pterygoid; from there it extends around the end of the mandible, making a large belly at the posterior ventral end. It is inserted along the ventral face of the angular and wraps around the articular, so that it is on the inside of the mandible at the posterior end. MUSCLES .OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule (D. m.).—This muscle arises on the posterior face of the parietal, extends ventrally, and is inserted on the retroar- ticular process of the mandible. VARANUS Plate VII, Figs. 3, 4, 5 The almost snake-like skull of Varanus is a typical example of the streptostylic skull, with the bones of the skull more or less movable, espe- cially in the quadrate region. There is a joint between the frontals and the parietals which has possibilities of movement, while the quadrate with its loose articulation on the squamosal and pterygoid forms another movable element. In fact the jaws, pterygo-palatine, and the quadrate region are all movable, with the posterior part of the skull as a base. The fenestre are large so that the muscles have room for development. The large supratemporal fenestra serves as the origin of the temporal slip of the capiti-mandibularis, while the lateral fenestra gives it room for development. This fenestration approaches the ophidian type where the opening out has been complete. The musculature of the pterygoid region is very musch specialized in the streptostylic forms and is a cenotelic character. These special muscles could not have been present in the cotylosaurs or stegocephalians, where there is no need of them, as the skull is rigid. The special muscles for moving the upper jaw and the facial part of the skull arise on the parietals, epipterygoid and basisphenoid and are attached along the whole upper surface of the pterygoid from the articulation with the transverse 98 ANNALS NEW YORK ACADEMY OF SCIENCES to the quadrate. This type of musculature is carried to the extreme in the Ophidia, where the streptostylism is complete and practically all of the bones are movable. There is a sharp contrast between the strepto- stylic and the monimostylic types of musculature; the streptostylic repre- sents high specialization, with great mobility of the skull parts and the demand for many muscles, while the solid monimostylic skull is rigid with the bones solidly fixed and attached by strong sutures, while the muscles present are of a simpler kind, namely, those needed to raise and lower the mandible. There is much confusion in the nomenclature of the muscles owing to the fact that the mammal names are applied to them by most workers. The nomenclature would be cleared if the entire list of names were dropped and a new set adopted that had no direct reference to the names of the mammalian muscles.* MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Capiti-mandibularis. (a) Capiti-mandibularis superficialis (C. m. s.). == Outer fibers of the capiti-mandibularis. (b) Capiti-mandibularis medius (C. m. m.). = Temporal of Bradley (whole mass). (c) Capiti-mandibularis profundus (C. m. p.). = Upper slip of the pterygoid of Bradley. == Pterygoideus externus of Mivart. Pterygoideus anterior (Pt. a.). —= Pterygo-mandibularis of Bradley. == Pterygoideus internus of others. Pterygoideus posterior (Pt. p.). == Lower slip of the Pterygoideus of Bradley. Pterygo-parietalis (Pt. par.) (Bradley). Pterygo-sphenoidalis posterior (Pt. sph. po.) (Bradley). MUSCLES OF THE DEPRESSOR OR DIGASTRIO GROUP (INNERVATED BY VII) Depressor mandibule (D. m.). MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Capiti-mandibularis.—This is the large temporal muscle mass, divided into three parts in this paper. 4The papers used in the study of Varanus were: Bradley (1903) and Watkinson (1906). ADAMS, PHYLOGENY OF THE JAW MUSCLES 99 (a) Capiti-mandibularis superficialis (C. m. s.) == Masseter portion. _ Arises on the quadratojugal, squamosal and quadrate. ~(b) Capiti-mandibularis medws (C. m. m.)—This is the inner part of the temporal sheet arising on postfrontal, prodtic, squamosal and quad- rate under the fibers of the outer or masseteric portion. These two slips are not separate. (c) Capiti-mandibularis profundus (C. m. p.).—The deeper portion of the mass. It arises on the parietal and is inserted on the coronoid along with the rest of the capiti-mandibularis. (A lower part of this muscle arises from the columella cranii and is considered as pterygoideus posterior. ) Pterygoideus anterior (Pt. a.) —This muscle arises on the whole outer surface of the pterygoid (except the branch to the palatine) and is in- serted on the posterior part of the jaw. Pterygoideus posterior (Pt. p.).—This with the exception of the lowest part arises on the columella cranii and is inserted on the mandible, posterior to the insertion of the capiti-mandibularis profundus. Pterygo-parietalis (Pt. par.) —This muscle is peculiar to reptiles with a rodlike columella cranii. It arises on the downward projection of the parietal and is inserted on the whole upper surface of the pterygoid, im- mediately in front of the articulation with the columella. It seems to represent a part of the inner layer of capiti-mandibularis profundus that separated off for the service of the pterygoid. The same might be said of the muscle following. ‘ Pterygo-sphenoidalis postertor.—This ads arises on the basisphe- noid below the gasserian notch and is inserted on the upper and lower surface of the pterygoid for its whole length to a level of the articulation of the basipterygoid process of the sphenoid and the pterygoid. It pulls the pterygoid upward and backward. This may represent a lower slip from the capiti-mandibularis profundus. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule (D. m.).—It arises on the parietal and nuchal fascia and is inserted in the end of the mandible. AVES GALLUS Plate VIII, Figs. 1, 2, 3 The musculature of the bird, Gallus, follows in most particulars that of reptiles. It offers one of the most convincing items of evidence that 100 ANNALS NEW YORK ACADEMY OF SCIENCES the birds and the reptiles are very close in their origin. The most im- portant characters of the bird skull are: (1) Great expansion of the brain case with pomronding changes in the base of the cranium. (2) Loss of the upper temporal arcade, the lower temporal arcade (quadratojugal and jugal) being left intact. (3) Radical changes in the pterygoid and palatine region where great changes occur even within the class. (4) Loss of teeth and assumption of a beak. (5) Loss of sutures and lightening of all the elements. The bird skull is fundamentally similar to that of the primitive pseudosuchian Hupar- keria capensis of Broom (1913). The maxille, jugal and quadratojugal articulate with the quadrate in true reptilian fashion, while the quadrate is movable as in many reptiles. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YJ,) Capiti-mandibularis. (a) Capiti-mandibularis superficialis (C. m. s.). == Masseter of Shufeldt and Gadow. (b) Capiti-mandibularis medius (C. m. m.). == Temporalis of Shufeldt, Gadow. (c) Capiti-mandibularis profundus (C. m. p.). Not present in Gallus. Pterygoideus anterior (Pt. a.). Pterygoideus posterior (Pt. p.). MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY V,) The capiti-mandibularis mass of the bird is divided into separate muscles, and we assume that they are represented in the reptiles as un- separated parts of the capiti-mandibularis, and for that reason they are given the names used in the reptiles. (a) Capiti-mandibularis superficiahs (C. m. s.).—This muscle may be divided into two parts; one rises as a tendon from the bony ridge of the squamosal, above the auditory entrance; the other head which is fleshy arises from the quadrate. The insertion on the mandible is by ADAMS, PHYLOGENY OF THE JAW MUSCLES 101 tendon and by a fleshy slip; the tendon is inserted on the coronoid process and the fleshy slip extends along the outside of the mandible. This muscle is the most important of the mandible, as it extends along the side and has a very wide attachment. (b) Capiti-mandibularis medius (et profundus) (C. m. et p.).—This muscle, usually called the temporal, is assumed to represent the middle and deep part of the reptilian capiti-mandibularis. The region for its origin is much reduced and there is no room for much differentiation of this part of the muscle. It fills the temporal fossa in the bird. It arises from the bones surrounding the fossa, extends downward, posterior to the postorbital process, and is inserted on the coronoid process of the mandible. Pterygoideus anterior (Pt. a.).—This is a large muscle that covers the floor of the skull at the posterior part of the palatines. It arises along this posterior part of the palatines, spreading out over this to a part of the pterygoids and the orbito-sphenoid. The insertion is on the under side of the articular process and along the inner side of the mandible. This muscle pulls inward and forward on the mandible, thus pulling the quadrate forward—a movement that is very important in the Psittaci, where the maxille are raised with the anterior part of the skull. Pterygoideus posterior (Pt. p.).—This is a smaller muscle that crosses the pterygoideus anterior, going under it. It arises on the orbital process of the quadrate and is inserted on the inner side of the mandible near the posterior end. It draws the mandible backward and pulls down on the quadrate, thus aiding in the closing of the jaw. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule (1). m.).—The depressor of birds is the same as that of reptiles and amphibians, being a part of the C,md of Ruge and innervated by the seventh nerve. In the birds it is short and thick, more like the same muscle in the Chelonia than like that of Sphenodon or Varanus. It arises on the squamosal as in the Chelonia, as this region has grown out laterally, so that the origin on the parietal is no longer available. It arises along the ridge of the squamosal and is inserted on the retroarticular process as in reptiles. It opens the mandibles with the aid of some of the long, ventral hyoid muscles of the throat region. 102 ANNALS NEW YORK ACADEMY OF SCIENCES MAMMALIA The jaw muscles of the mammals are remarkably constant in character throughout the group, except in the monotremes and some edentates where extraordinary conditions occur. Throughout the group the muscles are closely correlated with the dentition and with function. The chewing muscles are limited to the digastric, masseter, temporal, pterygoideus externus and pterygoideus internus. ‘There is much individual variation in these muscles, but they are always present, except the digastric, which is absent in some monotremes and edentates, and the internal pterygoid, which is sometimes not differentiated from the temporal. The temporal fosse of the mammals are opened out, so that there is free play for the muscles, except where there is a secondary covering of plates. The ramus mandibularis of the trigeminus nerve innervates all the muscles of mastication except the posterior belly of the digastric and its allies. 'The muscles innervated by V, represent what remains of the capiti-mandibularis of the reptiles. The temporal is the largest muscle of this group in most of the mammals. It is closely associated with the masseter, which is a slip that has separated completely in the mammals, but still remains a part of the temporal mass in the reptiles. The tem- poral is variable in its size, as the masseter is often larger, usurping its functions in the rodents and in some other groups. It is partially divided in the mammals, as we find it with a single head in Homo and with three in the monotremes, but although the condition may vary the origin and insertion remain quite constant. The masseter is much more variable than the temporal muscle. It is double-headed in man, and also is divided into two muscles in the mono- tremes, each with two slips, and we may have as many as five slips in the rodents. Its size and condition depend on the special conditions and the importance of the muscle. In the rodents, where it takes the place of the temporal to a certain extent, it is large and very much specialized. Its origin varies, as it may partly cover the temporal as in Didelphys, or may ~ extend forward, anterior to the eyes in the rodents, or divide into two separate muscles as in the monotremes. This muscle in the mammals is always associated with the development of the zygomatic arch and repre- sents the outer portion of the temporal mass that may be traced from the Pisces to reptiles, where the outer fibers of the capiti-mandibularis mass are always slightly differentiated from the deep fibers by having a diifer- ent direction, although there is no separation in the reptiles to the extent found in mammals. The pull of the masseter is usually slightly forward, —_—- ADAMS, PHYLOGENY OF THE JAW MUSCLES 103 against the pull of the temporal, which, together with the pull of the pterygoid muscles, gives the steadiness that is necessary in the mandibles. In many cases there is a connection of the masseter with the auditory region. In Tamandua (Lubosch, 1908, p. 541) this small muscle is seen, as it were, in the process of splitting off from the masseter and attaching itself to the tympanic. Bradypus villosus (Lubosch) shows this same condition, where a small muscle extends from the angle of the jaw to the tympanic. This small muscle is innervated, according to Lubosch, by the auriculo-temporalis nerve. The tendency of the masseter to extend to the auditory region probably may go back to the reptilian condition, where this muscle was attached to the quadrate or to one of the bones in this region. The pterygoid muscles arise on the basicranial or pterygoid region and, although usually small, they are of importance in the working of the jaws. They vary in form in different groups and the relation between the pterygoids and the dentition is very close. They are largely devel- oped in herbivorous but small in carnivorous mammals. They function in giving the jaw steadiness in opening and closing; they prevent the heavy temporal muscles from tearing the mandibles apart in forms with a loose symphysis and they make possible the grinding motion of the teeth in herbivorous forms. The edentates and monotremes offer excep- tional conditions, for here the reduced or modified condition of the man- dible makes the pterygoid muscle of little importance. The internal pterygoid is the more important of the two, as it aids in the closing of the jaw and pulls inward against the pull of the temporal, masseter, etc. The external pterygoid pulls the jaw forward, out of the glenoid cavity, and assists in this way in opening the jaw and in the forward movement of the jaw in herbivorous forms. The origins of these muscles are plainly seen in mammalian skulls and the condition of the pterygoid region has probably been very much modi- fied by their action, as a comparison with the reptilian condition shows that the pterygoid region is pinched in and pulled to the rear. We assume that this condition has been brought about largely by the action of ptery- goid muscles. In cynodonts the opposite pterygoid bones meet in the mid line, but in mammals the pterygoids have become much reduced and separated so as to leave the primary floor of the brain case exposed (basi- sphenoid, presphenoid) (Gregory and Adams, 1915). The capiti-mandibularis profundus (external pterygoid) of the reptiles seems to be in a favorable position to give rise to the whole pterygoid mass of the mammals, since it is inserted on the coronoid region of the mandible, and might easily shift its insertion down on the inner side of LA 104 ANNALS NEW YORK ACADEMY OF SCIENCES the upgrowing dentary without interfering with the other muscles. No doubt its importance increased when the new joint was formed between the dentary and the squamosal and when the old anterior pterygoid muscle became reduced. Its subdivision into two slips followed, which are the external and internal pterygoid of mammals. The digastric muscle of mammals (Fig. 4) represents a part of the second constrictor of the Pisces, joined with one of the ventral muscles of the throat region (A, V,). It is a muscle with two bellies, a tendon usually separating them, but this varies in different forms; so we may say that the muscle varies from the so-called monogastric to the typical double-bellied condition. As stated below, the muscle is constant in mam- mals with the exception of monotremes and some edentates. It is the only compound muscle in the muscles of the jaw and represents two muscles, one innervated by the facialis, the other by the ramus mandibu- laris trigemini, joined end to end, but still retaining the old innervation. The older anatomists all homologized the posterior belly of the digastric with the depressor mandibulee of reptiles and amphibians, but the work done on the innervation by Schulman, Lubosch, Ruge and others has shown that there is a common origin for them, but that they represent different slips from the same constrictor. The variation of the digastric has been discussed re Chaine, Toldt, Bijvoet, Parsons, Rouviére, Fiirbringer, Dobson, Futamura and others, so that there is not much left to work out in this line, although the inter- pretations of the authors are very variable. Chaine (1914) classifies the digastric of mammals as follows: (a) Those with two bellies: Macropus Bradypus Delphinus (Toldt) Artiodactyla Rodentia Carnivora Chiroptera Pteropus Insectivora ° Simiz Prosimiz (b) Those with a single belly: Hydrocherus Cavia — Dolichotes Lepus (c) Digastric absent: Monotremes Delphinus Tatusia Tursiops 5In Talpa ewropeus there is a small tendon from the posterior belly to the mandible. ee eee eee * ADAMS, PHYLOGENY OF THE JAW MUSCLES 105 Parsons’ views (1898, pp. 436-437) are expressed in the following quotations : The most important point to bear in mind, in considering this muscle, is that it is not always really a digastric, but that even when it appears monogastric it has a double nerve supply. Our knowledge of the anatomy of fishes tells us that the muscles developed from the first, or mandibular arch, are supplied by the fifth nerve, while those formed in the second, or hyoid arch, derive their nerves from the seventh. In three Ornithorhynchi I found a muscle running from the sub-hyoid septum, outward and a little forward to the man- dible, not far from the angle; it was supplied by the fifth nerve and lay super- ficial to the mylohyoid muscle, of which it appeared to be a delamination, and with which the fibers had the same general direction. In the same animal a single muscle runs from the long, tubular external auditory meatus to the sub- hyoidean septum; it is supplied by the facial nerve, and probably corresponds to the combined stylohyoid and posterior belly of the digastric. From this I am inclined to think that the anterior belly is an older muscle than the pos- terior, or, in other words, that the anterior belly is differentiated from the mylohyoid layer before the posterior belly is split off from the stylohyoid. This possibility may be the reason why the absence of the anterior belly of the digastric is rare in man, but the absence of the stylohyoid is fairly common. Describing the digastric with two bellies, Parsons says: In the first [type] the anterior and the posterior bellies are separated by a considerable length of tendon. The posterior belly runs forward until it is over the hyoid and then runs inward and meets its fellow from the opposite side, forming an arch. The anterior bellies of the digastric spring from this arch and go forward. The muscle is not attached to the hyoid but is connected by connective tissue. ; This type is found in many rodents (sciuromorphs, Pteromys), in most cynomorph monkeys and in certain anthropoid apes (orangs, chim- panzee). Parsons places under his second division those with a pseudo-mono- gastric muscle. Here the muscle seems to have one belly, but there is always a small rudiment of the median tendon. This type attaches to the mandible, midway between the symphysis and the angle, and instead of forming flat planes meeting along the median line of the neck they are rounded, as some expanse of mylohyoid separates them. Parsons’ third type is that found in man, where the bellies are distinct with a tendon separating them, the anterior bellies not meeting in the median line of the neck but forward near the symphysis. This type is found in most lemurs, many monkeys, especially the platyrhini, gibbons (Hylobates) and in many specimens of gorilla. The stages are all united by transitional stages. 106 ANNALS NEW -YORK ACADEMY OF SCIENCES S S SS SS | Qe j I vii’ ADAMS, PHYLOGENY OF THE JAW MUSCLES 107 Parsons also mentions a fourth type, where there is a true monogastric muscle in which the anterior or the posterior belly is suppressed. It is found in lagomorph, or hare-like rodents. The posterior belly is repre- sented by a small tendon in these. In many orangs the anterior belly is wanting and the posterior belly is attached close to the angle. Parsons’ division differs from Chaine’s in that he takes into considera- tion the condition of the anterior belly, whether joined with its fellow of the opposite side or free from it. Humphrey considered that the anterior belly was from the same myotome as the pterygoids, and the posterior belly was from the hyoid arch muscles, or hyoid myotome. He considered the tendon as a remnant of the myocommata connecting the two myotomes. These divisions of the digastric as given by Chaine and Parsons show some of the variations that are met with in this muscle. The posterior part of the muscle is not troublesome, but the anterior part, or the part innervated by nerve V,, has caused the anatomists much trouble. Some of the ideas as to the homology of the anterior belly are interest- ing, and show the diversity of opinion on this topic. Bijvoet (1908) gives an interesting summary of the ideas of different authors as to its origin. He considers that Ornithorhynchus shows the primitive stage of the DESCRIPTION OF FIGURE 2 Variations of the digastric in mammals. (Mainly after Chaine and Parsons.) The digastric muscle is found only in typical mammals and is not clearly recognizable in the monotremes. It is a compound muscle typically consisting of anterior and pos- terior bellies united by ligament. The anterior belly is probably a derivative of the primitive throat muscles of reptiles and is innervated by the mylohyoid branch of nerve V,. The posterior belly probably represents a separate slip from the stylohyoid muscle, and both muscles are innervated by closely associated branches of the seventh nerve. Probably both bellies of the digastric formerly converged toward the lower surface of the basi-hyal cartilages, along with the mylohoid and other muscles, and the tendinous portion between the anterior and posterior bellies may represent part of the fascia into which they were formerly inserted. Probably the most primitive type is seen in the monotreme Ornithorhynchus (10). Here the ‘“‘detrahens mandibule anterior’ (D. m. a.) (which may be a slip of the mylo- hyoid) may represent the anterior belly of the digastric, while the posterior belly is not yet separate from the stylohyoid (Parsons). The marsupial Macropus (5) shows well the association of the anterior belly (a) with the mylohyoid and the connection of both bellies with the basi-hyal. In most types the anterior and posterior bellies are both present and separated by tendon (as in Figs. 2, 4, 5, 6, 8, 9, 11). Hither one of the bellies may be vestigial or wanting. In No. 7 the posterior belly is reduced to a small tendon. In No. 13 the anterior belly is tendi- nous. The so-called monogastric types (3, 6, 9) generally show at least a vestige of the tendinous septum between the two bellies. In Nos. 1, 12 the digastric is entirely absent, being functionally replaced by other muscles. The posterior belly usually arises from the paroccipital process of the exoccipital. The insertion of the anterior belly varies greatly as well as its relations both to its fellow of the opposite side and to the mylo- hyoid (cf. Nos. 2, 3, 7, 9, 11). It is primitively inserted on the inferior border of the mandible beneath the masseter, but may shift either to the region of the symphysis (2) or to the posterior part. 108 ANNALS NEW YORK ACADEMY OF SCIENCES formation of the digastric and that the anterior belly is the detrahens mandibule, a muscle related to the stylohyoideus. Chaine (1914) thought that the digastric came from a muscle that originally stretched from the jaw to the sternum, that it lost its hold on the sternum and moved first to the vertebre and then to its hold on the mastoid. He accounted for the tendon between the bellies of the digastric by assuming that it was a remnant of the segmental areas found in primitive muscles. Dobson does not consider the digastric. Futamura (1906, 1907) had some interesting ideas on the origin of the digastric of man. In the first paper on the digastric of man he says: “The digastric is at first entirely supplied by the nervus facialis; later, as the anterior belly becomes constricted off from the posterior, the former obtains its motor nerve secondarily from the nervus mylohyoideus” (translation). He recants this in a later paper (1907) as follows: Der proximal Teil des Digastricus teilt sich in zwei Teile deren vorderer am Reichertschen Knorpel inseriert, deren hinteren um die hintere Seite des Knorpels herum ventralwiarts verliuft und am ventralen Ende des Meckelschen Knorpels inseriert. Der Muskel wird von zwei Nerven bereits innerviert; N. facialis und N. mylohyoideus. Beim Menchen glaubte ich aussprechen zu diirfen dass die zwischensehne an der doppelten Innervierung des Muskels schuld sei. Das kann aber doch nicht der Fall sein, weil beim Schwein, bei dem der Biventer keine zwischensehne besitzt, doch die zweifache Innervierung nachzuweisen ist. Gegenbaur (1898, p. 632) held that the anterior belly of the digastric came from the mylohyoid by splitting. He took the anterior belly from the mylohyoid and the posterior belly from the depressor mandibule of the reptiles. He cited the horse with its peculiar condition, where there. is a secondary insertion of the posterior belly on the angle of the mandi- ble, as an indication of this. His (1885, p. 92) derived the digastric from the sterno-cleido-mastoid, which he separates into two parts: the mylohyoideus and the outer tongue muscles. He derives the anterior belly of the digastric from the super- ficial layer and the posterior belly from the deep layer of the sterno- cleido-mastoid. Leche (1889) had the same idea as haiti and thought that tie digastric was a muscle with a single nerve and that it acquired, second- arily, a second supply from the trigeminus. Rouviére (1906) derived the anterior belly from the same origin as the geniohyoid and says that in the fishes, amphibians, reptiles and birds, only the anterior belly is present. He derives the posterior belly from ADAMS, PHYLOGENY OF THE JAW MUSCLES 109 the m. jugularis transversus, the same mass from which the stylohyoid is separated. He considers the digastric to be the result of the joining of these two muscles. Toldt (1908) gives the following points on the anterior belly of the digastric: (1) The digastric as such is found only in the mammals. The attempts to derive it from the muscles of the non-mammalia have not been success- ful. The hinder belly is not the depressor mandibule of the Sauropsida nor is it derived from the depressor of the monotremes. (Schulman shows that it is not derived from the depressor of monotremes. ) (2) The depressor of the monotremes is a special primitive condition and is a slip from the masseter innervated by V,. The writer thinks this is not a primitive condition but a very specialized condition in a primitive form. (3) The anterior belly of the digastric has its origin with the m. mylohyoideus muscle and belongs with the visceral muscles that extend along the floor of the mouth. They are innervated by V3. (4) The posterior belly is a part of the stylohyoideus in the lower vertebrates and is originally a visceral muscle intercalated between the musculature of the mouth floor and throat and directly or indirectly con- nected with the tongue bones. (5) The joining of this originally separate muscle to the digastric, as well as the identity of the hinder belly and the stylohyoideus, is shown well in the monotremes. The line of separation is shown by the inscriptio tendinea. . Toldt correlates the condition of the digastric with the type of food that the animal eats and with the question whether the food is held in the mouth or swallowed immediately. This, he thinks, gives an explana- tion of the joining of the forward bellies in some forms and separation of them in some of the carnivorous forms. But a comparison of the varying forms of digastric seems to show that there is no correlation with food habits, as there seems to be no definite functional criteria by which the different conditions may be classified. From a review of the literature on the digastric the variations are plainly evident both in the muscle and in the ideas concerning it. There seems to be no very stable insertion for the anterior belly. Its insertion _ varies from the inside of the chin, as in Homo, to the posterior part of the mandible, on the angle in some other forms. Only the anterior part is of uncertain origin, as most of the writers agree on the derivation of the posterior belly. The anterior part lends itself to hypotheses, as nothing definite seems to have been brought forward at the present time 110 ANNALS NEW YORK ACADEMY OF SCIENCES and all may be more or less right. The double innervation and the tendon seem to make certain the fact that the muscle has a double origin. Some of the older writers speak of a single-bellied digastric, but most of them agree that some evidence of the double origin always exists, and that in the monogastric muscles remains of the tendon are in evidence in the middle of the muscle, or, as in Lepus, the anterior muscle may be almost gone while the tendon remains to represent the junction of the two parts. In a few forms undoubtedly one of the muscles is missing— that is, one belly is missing and it is not really a monogastric muscle but a single belly in the sense that either the anterior or the posterior belly has disappeared, and not that the one represents both bellies. So far I have spent very little time on the mylohyoid and the other ventral muscles, reserving them for future work on the comparative musculature throughout the vertebrates. The discussion of this phase of the jaw muscles is made very brief and merely points out some of the comprehensive work of Toldt, Chaine, Rouviére, Bijvoet and others on the digastric musculature in the mammals. The relation of the jaw muscles to the special types of dentition is very close throughout the mammalian groups. In fact a highly differentiated muscle system in which each muscle does a certain type of work alone makes possible the highly specialized dentitions of rodents and ungulates. The teeth of mammals are, roughly, of three kinds—herbivorous, carniv- orous and degenerate. The herbivorous dentition is correlated with the peculiar type of condyle and glenoid joint that makes its specialized work possible. The condyle of the typical herbivorous animal is much rounded and the articulation in the glenoid cavity is flat, so that there is much freedom of movement. In chewing the jaw is rotated in a lateral, antero- posterior and vertical movement, so that to accommodate this movement the articulation must be very loose. Accordingly, there is always a well developed pterygoid region in the basicranial region, with well developed pterygoid muscles. This strong development of the pterygoid muscles is characteristic of Macropus, Halmaturus, Castor, Scwurus, Hquus and Bos. In these animals the molar teeth bear cross-ridges and the transverse mo- — tion needed for trituration is given by the strong pterygoid muscles. Many herbivorous mammals chew on one side at a time. The pterygoid muscle, acting in connection with the large temporal and masseter muscles of one side, make this movement possible. In the rodents where the symphysis is weak the pterygoid muscles also counterbalance the pull of the huge masseters, as in some of the forms with a weak symphysis the pull of the masseters alone would tear the jaws apart. The carnivorous mammals have an entirely different ar- ADAMS, PHYLOGENY OF THE JAW MUSCLES Eel rangement, as their jaw action is primarily a straight opening and closing movement, either a hard, steady pull, or with a snap. The opposite halves of the mandible are usually strongly fastened together at the symphysis. The condyle is lengthened out laterally toward the median line and the glenoid cavity has a large protecting shelf to give a firm hold on the condyle. In fact in some of the carnivorous types with strong jaws the articulation is locked, so that the borders of the glenoid cavity must be broken in order to separate the mandible from the skull (Gulo luscus). With the shearing teeth and the locked type of articulation for the con- dyles of the jaw the pterygoid muscles are of little value and in carniv- orous forms are always weak, as in Canis, Gulo, Lutra, Didelphys. In these animals the basicranial region of the skull shows the reduction of the pterygoid muscles. MONOTREMES Plate IX, Figs. 1-7 Skull— The skull and jaws in both Ornithorhynchus and Echidna are of very aberrant and more or less degenerate types. In both genera, also, the pterygoid region is highly modified, and thus the homology of the so-called pterygoid elements is open to question. Ornithorynchus re- quires fairly strong jaws for the crushing of small mollusc shells, while Echidna has practically vestigial jaws and depends mostly on the tongue muscles. The condition of the jaw musculature in the monotremes is quite sug- gestive of the reptiles. The massed condition of the temporal-masseter group suggest the condition of the capiti-mandibularis of the reptiles. The head muscles as a whole seem to be homologous with those of other mammals, especially as regards the temporalis-masseter, pterygoideus externus and muscles of the ventral hyoid group, with the exception of the anterior belly of the missing digastric, which may be represented by the muscle called depressor mandibule anterior. However, this hyoid region in the monotremes is very specialized, so that the derivation of the an- terior belly from this region is rather obscure, although some anatomists hold this opinion. It is probably a slip from the mylohyoid. The duck- like bill of the Ornithorhynchus requires a special musculature which is developed from the V, muscles. The monotremes are so different from other animals in many important details of their myology that it is probably correct to assume that they split off from the mammalian stem at a very early period. This assump- tion is strengthened by the fact that the osteology and soft anatomy are L1> ANNALS NEW YORK ACADEMY OF SCIENCES also very aberrant, so that it is not strange to find different conditions in the musculature. The jaw muscles of monotremes include the following: MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,). Masseter | Pterygo-tympanicus Temporalis Depressor mandibule anterior Pterygo-spinosus Detrahens mandibulee MUSCLES OF THE DIGASTRIC GROUP (INNERVATED BY VII) These are not present. Monotremes have the following peculiar conditions of the jaw muscles: They have no true digastric. The masseter and temporal muscles are massed together. They have no pterygoideus internus. Presence of the pterygo-spinosus and pterygo-tympanicus. Presence of the detrahens mandibule instead of the digastric. Extensive development of the mylo- hyoid group of muscles. | Absence of the digastric.—The digastric is fairly constant in the mam- mals except monotremes, edentates and some Cetacea. Perhaps it is ab- sent in the monotremes because they separated from the mammal stem at a very early period and thus have missed this arrangement. Ornitho- rhynchus with its fairly large jaws needs a depressor, and this function is filled by the detrahens muscle and by the depressor mandibule anterior of the hyoid group. Hchidna is so degenerate in the mandibular region that there is very little need for a specialized depressor. Other mammals in which this muscle is missing have degenerate jaws. Chaine mentions Tatusia of the edentates and Delphinus of the Cetacea, where the true digastric has been lost. | Imperfect separation of the masseter and temporal.—The condition of the masseter-temporal mass in the monotremes is very suggestive of the capiti-mandibularis in the reptiles, as it is not differentiated as much as in other mammals. The mass has several heads, but the separation is not so complete. The peculiar shape of the skulls in the monotreme may be responsible for this condition. There is very little room for muscles in Echidna, as the mass is completely covered by bone. Schulman (1906) gives a division of the muscles showing their complexity and tendency to break up into small slips. Absence of the internal pterygoid.—The absence of the pterygoideus internus is striking, as it is one of the constant muscles of the mam- malian skull. Some writers gave the monotremes an internal pterygoid, ADAMS, PHYLOGENY OF THE JAW MUSCLES 113 but from the recent work of Schulman (1906) it seems that this is a mistake. Evidently its separation from the temporal mass is not com- plete. Schulman says that the pterygoideus internus of Meckel is inner- vated by a nerve that supplies the temporalis and assumes that this muscle is a part of the temporalis, which he calls “caput anterius.” He offers the suggestion that it might have appeared in the mammals after the monotremes had been cut off from the mammalian line. He says: Der M. pterygoideus internus wird, aller Wahrscheinlichkeit nach, bei Ornithorhynchus vermisst. Nicht einmal das Mikroskop zeigte in der ventral und medial von dem R. III trigemini befindlichen Gegend Muskelreste zwischen dem Schidel und dem Unterkiefer, d. h. an dem Platz, wo dieser muskel bei den Siugethiere vorzukommen pfiegt. Ob die Wesenheit des M. pterygoideus internus bei den Monotremen ein Riickbildungserscheinung ist, oder ob dieser Muskel erst mit dem Typus der iiber den Monotremen stehenden echten Siugethiere enstanden ist, bleibt vorliufig eine offene Frage. The homology of the “pterygoid” in monotremes is in question, and if the conclusions of some of the authors are true, the small muscle called the pterygo-spinosus might be called a pterygoid muscle but for the fact that it appears in man as a rudiment or an anomaly and appears as a regular element in Cholepus, Tamandua, Manis, Tatusia and Dasypus. Presence of the pterygo-spinosus and pterygo-tympanicus.—The pres- ence of the pterygo-spinosus and the pterygo-tympanic suggests the un- settled state of the pterygoids in mammals, for in the animals in which it is found the attachment greatly varies. Its positions are as follows: (a) It is attached to the sphenoid in man and to the lamina lateralis of the pterygoid process (Thane, McAllister, Poland, Kreutzer). (b) It is attached to the ligament assessorium mediale (Kreutzer). (c) It is attached to the mandible (Gruber, Kreutzer). (d) It is attached to the pterygoid internus (Poland, Gruber, Kreut- zer ). From these variations Lubosch believes that the insertion is lost. Schulman (1906) says: Es kann daran gedacht werden, die bei den hdheren Siugethieren vorkom- men zwei Muskeln auf das Velum palatinum sich ausbreitenden M. tensor veli tympani und den an einem unbeweglichem Pterygoidknochen sich anheften rudimentiiren M. pterygo-spinosus, vor einen, bei den Promammalia mit einem beweglichen Pterygoideum verbunden, undifferenzirten Muskel abzuleiten, der danach as Muttermuskel fiir die M. tensor veli palatini und pterygo-spinosus anzusprechen wiire. Doch bedarf es zur Sicherung dieser Vermutung viel ausgebreiteterer Untersuchungen als die hier angestellten. Auch wire heirbei die Frage zu erértern, ob die Beweglichkeit des Pterygoids von Ornithorynchus eine primiire oder sekundire ist. 114 ANNALS NHW YORK ACADEMY OF SCIENCES The most typical attachment of this muscle is to the annulus of the ear and to the pterygoid bone from the mandible. In spite of all the work done on the pterygoids of mammals, one may say that they are of rather unsatisfactory status as yet. Gaupp assumes that they are derived from the parabasals and that they are not homologous with those of other mam- mals. It is hoped that the problem will be solved as a result of Watson’s recent studies on the development of the skull in the monotremes. Presence of the detrahens mandibule.—This pair of muscles serves as the depressor of the mandible in monotremes where the digastric is en- tirely absent. It originates on the mastoid and squamosal region of the skull, wraps around the lower part of the head, and is inserted on the lower edge of the mandible with a good attachment on the sides, so that it has a firm hold. It is peculiar to the monotremes and is not homolo- gous with the parieto-mandibularis (depressor mandibule) of reptiles which has a similar position and function. The reptilian analogue is innervated by the seventh nerve, while the detrahens mandibule in mono- tremes is innervated by the trigeminus. Schulman, Toldt, Bijvot and Gaupp believe that it belongs to the dorsal muscles of the head. Gaupp and Schulman both believe that it is a slip of the capiti-mandibularis (masseter portion) of the reptiles that has slipped back to act as the depressor. The earlier investigators thought that it was a part of the mammalian digastric, as they did not know of the nerve supply. All of these investigators have changed their opinion with the working out of the innervation by Schulman, who showed that it is innervated by the trigeminus nerve. Schulman says: Es unterliegt somit meiner meinung nach keinen zweifel, dass der M. de-- trahens mandibule zu den dorsalen Kaumuskeln gehort, und kKeinen Bauche des M. digastricus mandibule der héheren Mammalia homolog ist. The meaning of this musculature in the monotremes seems to be that the reptilian articulation of the mandible to the jaw was lost, as the Reichert Theory would assume, and that in the shifting of the muscles in monotremes the new depressor was developed from the capiti-mandib- — ularis instead of from the depressor mandibule or its mother mass. This would place the monotremes in a different line, and their anatomy justly places them at some distance from the rest of the mammals, so perhaps this conclusion is not far wrong. , ADAMS, PHYLOGENY OF THE JAW MUSCLES até DIDELPHYS Plate X, Figs. 1, 2 The skull of Didelphys is remarkably similar to that of lower Eocene Carnivora in so far as it has a very narrow brain case, high sagittal crest, long heavy muzzle, stout zygomata and stout curved mandibles. The pterygoid bones are reduced, as is frequently the case in carnivorous mammals. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV;) Masseter Pterygoideus internus Temporalis Digastricus (pars anterior) Pterygoideus externus MUSCLES OF THE DEPRESSOR OR DIGASTRIOC GROUP (INNERVATED BY VII) Digastricus (pars posterior) MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP . (INNERVATED BY YV,) Masseter—This is a very large and strong muscle, arising on the under side of the zygomatic arch and from the fascia extending up over the temporal muscle. The insertion is on the posterior, ventral part of the angle of the mandible. Temporalis.—This is a large muscle filling the temporal fossa and ex- tending to the high sagittal crest. The insertion is on the coronoid process of the mandible. ; Pterygoideus externus.—Arises behind the pterygoideus internus on the alisphenoid and is inserted on the inner side of the mandible. Pterygoideus internus.—Arises on the pterygoid wing of the alisphe- noid and is inserted on the inner side of the angle of the mandible. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) . Digastricus posterior—This is quite a large muscle, arising on the mastoid and inserted on the inner side of the mandible, well forward. 116 ANNALS NEW YORK ACADEMY OF SCIENCES SOLENODON Plate X, Figs. 3, 4 The skull of Solenodon is remarkable for its degenerate zygomata, for the great elongation of the muzzle, verticality of the enlarged anterior incisor, small brain case with low sagittal crest, and sharply tritubercular molars. MUSCLES OF THE ADDUOCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Masseter | Pterygoideus internus Temporalis Digastricus (pars anterior) Pterygoideus externus MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Digastricus (pars posterior) MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Masseter.—A thick, heavy muscle arising on the zygomatic process of the maxillary and from the fascia over the temporalis. It wraps around the posterior angle of the jaw. Temporalis.—A large muscle arising in the temporal fossa and on the squamosal. The insertion is on both the inner and outer surfaces of the coronoid process. Pterygoideus externus——A small muscle with a small origin on the alisphenoid. Inserted on the inner side of the head of the condyle. The muscle is slight, as the animal has a carnivorous dentition. Pterygoideus mternus.—Arises in the pterygoid fossa and is inserted on the inner side of the posterior angle of the mandible. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Digastricus (pars posterior ).—This is a large heavy muscle which arises on the mastoid process and is inserted on a bony process on the lower side of the mandible under the coronoid process. ADAMS, PHYLOGENY OF THE JAW MUSCLES 117 MUS Plate X, Figs. 5, 6 The relations of the jaw muscles to the dentition and form of jaw and skull are nowhere more apparent than in the rodents. The rodents have a great development and differentiation of the masse- ters which overshadows the temporals. This is characteristic of the group and the jaw action is very complex. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY Y;,) Masseter Pterygoideus internus Temporalis Digastricus (pars anterior ) Pterygoideus externus MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP. (INNERVATED BY VII) Digastricus (pars posterior ) MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Masseter—This muscle is very large and much subdivided. It arises along the zygomatic arch, extending some distance in front of the eyes where the zygomatic process of the mandible is much expanded to give it a foundation. The posterior part of the expanded mandible forms the base of the insertion. This insertion is very large in comparison with that of most mammals. Temporalis.—This muscle arises in the temporal fossa and is inserted on the inner side of the mandible. It is of medium size in Mus, although in some of the rodents it is much reduced. Pterygoideus externus.—This muscle arises on the pterygoid fossa and is inserted on the mandible, where it has a good hold on the expanded angle. It holds against the pull of the masseters and pulls the mandible forward. Pterygoideus internus.—This muscle is much larger than the external pterygoid, arising in the pterygoid fossa and inserted with a large inser- tion on the large expanded angle of the mandible. It holds against the pull of the other temporal muscles and prevents the tearing apart of the jaws where the symphysis is weak, as it is in many rodents. 118 ANNALS NEW YORK ACADEMY OF SCIENCES MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Digastricus (pars posterior).—The digastric as a whole is a large muscle arising on the mastoid and inserted on the lower edge of the mandible, posterior to the symphysis. FELIS The cat furnishes a good example of a specialized carnivorous jaw. with chiefly orthal or vertical movement. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Masseter Pterygoideus internus Temporalis Digastricus (pars anterior) Pterygoideus externus MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Digastricus (pars posterior) MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY V,) Masseter.—This has three layers in the cat, but it has about the same insertion and origin as in man. Temporalis—This is more extended than in man, reaching to the parietal crest. Its insertion is on the outer side of the coronoid process. Pterygoideus externus.—Arises in the external pterygoid fossa between the foramen rotundum and the spheno-palatine foramen. Its insertion is on the inner side of the coronoid process. ‘The coronoid process is very high and the condyle very low, sc that the muscle has changed its inser- tion. Pterygoideus internus.—Arises in the pterygoid fossa in about the same position as in man. ‘The insertion is on the inner border of the mandible and extends back to the angle. Its fibers on the inner side go to the masseter, and it is partly united with the pterygoideus externus and the stylo-hyoid ligament. MUSOLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Digastricus (pars posterior).—The digastric as a whole arises on the mastoid and occipital bones. Inserted on the lower edge of the mandible, just anterior to the first premolar. It is entirely inside of the jaw. ADAMS, PHYLOGENY OF THE JAW MUSCLES 119 HOMO Plate X, Figs. 7, 8 Riegner (1906) gives the results of some interesting experiments that he had made upon chloroformed apes. He stimulated the jaw muscles of the unconscious apes and watched the jaw actions, which may be summarized as follows: The masseter lifts the jaw and pulls it laterally. The temporalis lifts the opened jaw. The pterygoideus externus opens the closed jaw to some extent, pulling it slightly medianward and toward the opposite side. The pterygoideus internus closes or lifts the open jaw and pulls in opposition to the masseter, 1. e., toward the opposite side. The digastric (anterior belly) opens the jaw. Without it a nom- inal movement to the opposite side takes place. The hinder belly has little to do with the jaw movements in the ape. The geniohyoid gives the jaw a straight pull in opening it. This work on the apes gives about the action that takes place in man, but it is not an entirely accurate account of what happens in some of the mammals with a different type of skull (see also Strasser, 1908). MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV;,) Masseter Pterygoideus internus Temporalis Digastricus (pars anterior) Pterygoideus externus MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Digastricus (pars posterior) MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV;) Masseter.—Arises from the lower border and inner surface of the zygomatic arch and is inserted on the outer face of the posterior end of the mandible and on the coronoid process. Temporalis.—Arises from the whole surface of the temporal fossa, ex- tends down under the zygomatic arch and attaches itself to a point of the coronoid process, the insertion extending slightly down on both sides. Pterygoideus externus.—Arises by two heads, from the under surface 120 ANNALS NEW YORK ACADEMY OF SCIENCES of the great wing of the sphenoid and from the outer surface of the ex- ternal pterygoid plate. It is inserted in a depression in front of the neck of the mandibular condyle and in the inter-articular fibro-cartilage and capsule of the temporo-maxillary articulation. | Pterygoideus internus.—Arises by two heads: one from the deep sur- face of the external pterygoid plate and another by a stout tendon from the tuberosity of the mandible. Both heads are inserted in a triangular area on the inner, posterior surface of the mandible. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP Digastricus (pars posterior).—The digastric as a whole arises in the digastric groove of the mastoid process of the temporal and is inserted in the lower, inner border of the anterior portion of the mandible. It is a two-bellied muscle, the two bellies being separated by a stout tendon. A shght tendon also attaches to the middle of the muscle to the hyoid bone. RECONSTRUCTIONS OF THE JAW MUSCLES IN CERTAIN EXTINCT VERTEBRATES PLACODERMI The great class of the Placodermi, including many specialized forms, apparently never attained true gnathostome jaws. Gregory says: All the Known ostracoderms appear to be aberrantly specialized in certain directions, but long consideration of their many peculiar characters has con- rinced me that they stand far below the true fishes and that the group as a whole may represent an important stage in the genealogy of the vertebrates. In the upper Silurian we have many forms, like Birkenia and Lasaniwus of the order Anaspida, Lanarkia and Thelodus of the order Heterostraci, without true gnathostome jaws, so far as has been discovered. The mouth in these forms was probably a sucking type with a sphincter around it. Dr. Gregory (1915) has the same idea: Of the many beautifully preserved specimens of Birkenia, Lanarkia, Dre- panispis, Pteraspis, Tremataspis, Cephalispis and allied genera, none show the ‘least indications of an internal skeleton, nor is there ever any trace of the branchial arches and internal jaws. . . . The ostracoderms represent a stage in chordate phylogeny immediately preceding the acquisition of a carti- laginous skeleton impregnated with mineral salts; their first visceral arches, if present, had not been transformed into primary or cartilaginous jaws; the process of cephalogenesis was in a low stage and the elements of their shelly exoskeleton were potentially homologous with cosmine, vasodentine and isopo- dine of the primitive ganoids. To that extent they stand in a “pre-gnatho- ADAMS, PHYLOGENY OF THE JAW MUSCLES 121 stome”’ stage of evolution and probably represent the forerunners of the ganoids and Tetrapoda, while possibly having remote relationships also in another direction with ancestral elasmobranchs. . . . The Antiarchi have advanced beyond the typical Ostracoderms in having the head sharply differ- entiated from the thorax and the mouth armed with functional jaws, which are fashioned from the dermal skeleton. But not even the exquisitely pre- served specimens of Bothriolepis described by Patten (1912) show any traces of the cartilaginous jaws, branchial arches or cartilaginous axial skeleton. In another passage this author writes: The upper Silurian Birkenia of Traquair apparently had no biting jaws and may have sucked in small particles of food like the larval lamprey. Well preserved material showed that none of the Ostracoderms had cartilaginous jaws or teeth, but the dermal plaques around the oral hood sometimes func- tioned as jaws. Typically carnivorous habits, involving true cartilage jaws, true teeth, and both paired and median fins, are first shown in the Acanthodian sharks of the upper Silurian and Devonian. We may therefore assume that cartilaginous jaws first appeared as such in the true fishes (elasmobranchs). In the Silurian and Devonian ostra- coderms there is a progressive series that shows some of the many attempts to produce workable jaws. The Anaspida, though fish-like in form, have progressed but slightly toward the true fishes. Lasanius had some struc- tures back of the poorly formed head that suggest dermal gill supports. In certain Heterostaci (Thelodus and Lanarkia) the skin was covered with denticles that resemble those of elasmobranchs. These denticles would strengthen the skin and give the muscles of the skin fascia much better support. The Drepanaspide show marked progress in the strengthening of the skin by the formation of plates of different sizes. Drepanaspis and Pteraspis show a differentation in the head region, but it is more to be compared to the hard covering of some insects, as the cartilaginous sup- ports of the interior were feeble or lacking. The mouth was unlike that of either elasmobranchs or teleosts, but seems to have been a wide slit stiffened by dermal scutes. The Ostrastraci show more specialization along this same line, but with no better results. The, clumsy plates of Cephalaspis, Tremataspis, etc., give little promise of anything that would be much better than the arthropod jaw. The placoderm fishes of the order Antiarchi made a more clearly defined attempt to have movable jaws formed from dermal plates. A study of the fossils shows that they had a mouth that was functionally analogous to the mouth of fishes—that is, their dermal jaws correspond in position, but are not homologous with dermal premaxille, maxille and mandibles. The head is slightly movable on the shoulder, as in Arthrodira, and the jaws could apparently move laterally as well as vertically. Patten (1912) holds that they were bottom- 122 ANNALS NEW YORK ACADEMY OF SCIENCES FIGURE 3 1. Outline restoration of Coccosteus, a primitive arthrodire. After Patten. The well-armored head and thorax are sharply differentiated from each other. They are connected by a peg-and-socket joint in the neck region. . 2. Outline restoration of an antiarch, Bothriolepis. After Patten. Head and thorax are well defined, but the head is less movable than in Coccosteua-. Very probably the oral and the branchial pouches with their respective muscles were becoming differentiated from each other. 38. Longitudinal section of Bothriolepis, showing the lack of endoskeletal structures, such as calcified visceral arches and the dermal character of the functional jaws. After Patten. 4. Outline of Pterichthys. After Patten. ADAMS, PHYLOGENY OF THE JAW MUSCLES 123 feeders and either took slow-moving animals that they could engulf or fed on vegetation. Patten says that they were herbivorous, for he found carbonaceous residue in their bodies. The right combination of cartilage jaws covered with bony dermal plates was first worked out by the ganoid fishes, ancestors of the modern fishes on the one hand and of the land-living vertebrates on the other. DINICHTHYS Plate XI, Figs. 1, 2 The great arthrodires of the Devonian made the best pregnathostome attempt to form a mouth with skeletal supports, but they made the fatal error of trying to form those supports solely from the bony plates of the skin rather than from the branchial cartilages. Coccosteus and Dinich- thys both show in the skull a fine apparatus that serves for seizing their prey. The arthrodiran jaw must have been a formidable weapon, as it was armed with great sharp bony projections analogous to teeth. That these great jaws were much used for biting and shearing is shown by their worn shearing surfaces. Hussakof (1906) says: “The deep scars found on the outer side of certain Dinichthys plates also bear testimony to the savage attacks of their fellows.” The jaws seem to have worked on the principle of the joints of the insect leg, with most of the muscles attached chiefly to the plates of the body and head. The Arthrodira made another fatal mistake in that they moved the head perhaps more than the mandible. There is a joint be- tween the head and the shoulder plates (Fig. 2), with a good peg-and- socket articulation, so that while the mandibles remained more or less sta- tionary the great head with its dermal plates moved up and down against them ; thus we have the anomaly in the vertebrates of a relatively station- ary jaw and a movable head, just as though the mandible of the gnatho- stomes was attached immovably to the sternum, while the maxille and skull moved against it. It seems surprising that in the discussions as to the relationships of the Arthrodira so little importance should have been given to the peculiar motion of the head upon the thoracic shield, which is unknown among true Pisces. The movement of the mandible of Dinichthys has been very carefully studied by Dr. Hussakof (1906), to whose kindness J owe the opportunity of studying the great collection of arthodiran fossils in the American Museum of Natural History. The movement of the head upon the mandible appeared, however, to have received too little attention, and Shis I have accordingly studied with great care. 124 ANNALS NEW YORK ACADEMY OF SCIENCES The mandibles in the arthrodires were not stationary, but they have no sign of the ordinary piscine articulation even in the best preserved fossils (Fig. 4). They appear to have been attached to the skull plates some- what as the scapula in mammals is attached to the body, namely, by liga- ments, muscles and connective tissue. From the mechanical point of view, there seems to be three possibilities for movement in these arthro- diran jaws: first, they might have had the muscles so arranged that there would have been a synchronous movement of the head and jaws, and from a study of Dinichthys this seems to be the best arrangement, as it is the one that lends itself best to the arrangement of the muscular system; secondly, the jaws might have been arranged so as to work against the skull, but the movable joint at the back of the head seems to make this rather disadvantageous, as the head is not a stationary structure, and part of the force of the movement would be lost, as the joint in the neck would give and the head would be pushed back until it touched the dorsal shield. The usual joimt or condyle in the neck region is not prominent and must have been an uncalcified cartilaginous articulation, if any- thing, for the dorso-ventral movement of the head would tend to dislocate any ordinary articulation between the head and the neck. In brief, these agnathous forms developed their dermal plates just as the gnathostomes did, but while the gnathostomes ‘put the emphasis on the cartilaginous substratum and developed from it the principal struc- tures of the head and jaws, thus making the membrane bones subservient to the cartilage and finally drawing them in as a covering for the car- tilage, the ostracoderms and arthrodires put all the stress on the outer dermal plates and developed the movable parts from these elements, while apparently neglecting the development of the cartilaginous viseral arches. - The peculiar head structure of the Arthrodira seems to imply an equally peculiar musculature as follows: (1) The joint between the dermal plates of the head and dorsal shield implies the existence of muscles to raise and lower the head. (2) As stated above, there appears to be no surface on the mandible that could articulate with a quadrate in the ordinary piscine fashion, so that from the present knowledge of arthrodiran anatomy the adductor mandibule of the Pisces could not be applied to these forms. Thus it seems probable that any system of mus- culature that would be effective in its mechanical action would be entirely unfishlike. Accordingly, in Plate XI the musculature of Dinichthys is figured according to the mechanical requirements and follows no fish type. The movements of the head would require two large muscles in order to move the head up and down on the ginglymoid joint. One pair would be in the posterior region of the skull where the marks are plain FIGURE 4 Dermal jaw bones of various arthrodires, lateral surfaces; from specimens in the American Museum of Natural History. The dermal lower jaws of arthrodires were probably not connected with the upper jaw by means of quadrate and articular cartilages as in true fishes, but may have been fas- tened in the thick dermis surrounding the oral cavity. 1. Stenograthus gracilis.—This represents a long-jawed specialization from a Dinich- thys-like type. 2. Dinichthys intermedius._-The shearing portion of the jaw is raised above the plane of the horizontal ramus which was probably embedded in the thick dermis. 3. Diplognathus mirabilis.—A very peculiar offshoot of the coccosteid type. The sym- physeal border of the lower jaw bears tooth-like projections which apparently indicate that each jaw plate could be twisted on the long axis in a manner impossible in true fishes (Dean). 4. Dinichthys curtus. 5. Dinichthys intermedius.—To the upper end of this specimen on the outer side is attached a triangular bone which may have served for the insertion of muscles and fascia movably connecting the mandible with the inner side of the skull, somewhat as the scapula of mammals is connected with the body. 126 ANNALS NEW YORK ACADEMY OF SCIENCES in the specimens, showing that there were large muscles there. These muscles might be called the levator capitis muscles, as they raise the head. From the insertion areas this appears to have been a double muscle, one on each side of the median line. The attachment would be under the dorsal shield, where there is a strong keel that would serve as a good insertion for so important a muscle. The depressor capitis must have arisen on the heavy, inner part of the skull, and the specimens show areas that might well have served for this purpose. There is a large depression at the posterior end of the inner side and a strong ridge along the side of the large paired elements that might have covered the cartilage protecting the brain and might have. given a base for the muscles. The insertion of this muscle is problematical. It could hardly be inserted on the plastron, for there it would be in the way of the digestive tract. The only other likely place for the insertion of the depressor capitis muscle would be on the so-called “clavicular element,” as the muscle could not have been attached to any part of the skull itself. The problem of the musculature of the mandibles is even more of a puzzle than the musculature of the skull. This mandible has been inter- preted in various ways: as a. splenial by Eastman and as some other ele- ments by various writers. Whatever its history has been, it is apparently similar to nothing in the Pisces. If it is a splenial it is utterly unlike the splenial of the dipnoans, for they all show a distinct concavity on the outer side of the splenial for the reception of the Meckelian cartilage; and examination of the specimens in the American Museum of Natural History shows no arthrodiran that has any concavity for the Meckel’s cartilage. The splenial of Ceratodus is quite concave on the outer side and is shaped in a peculiar manner at the posterior end where the articu- lation with the quadrate takes place. There is none of this in any of the Arthrodira. If this mandible represents one of the outside bones of the enathostome mandible, the same difficulty remains, for the dipnoan shows that the outer elements are concave on the inside to make a place for the Meckelian cartilage. Thus the arthrodiran mandible seems to be some- thing quite different. From the texture of the outside of the mandible, it would appear that at least the anterior half has been on the surface, while the depressed, posterior half might have been imbedded in tissue. The shape of the posterior end of the mandible makes it very evident that it is more or less free, as is seen in the free end of the teleost maxilla or operculum, where the free end is always thin and blade-lke. From analogy, we might well conclude that the same is true in the Arthrodira. In the American Museum of Natural History a new mandible of Dinichthys, which will be fully described by Dr. Hussakof, shows a pecu- 4 ADAMS, PHYLOGENY OF THE JAW MUSCLES 127 liar triangular plate on the outer face, and at the posterior end this triangular plate is roughened for the insertion of a supporting cartilage or ligament. Very probably it articulated with the inside of the cheek plate or with some other external plate and not with a quadrate. In the mandible of Mylostoma Dr. Eastman (1906) found an irregular mass on the inner side which he interpreted as the Meckelian cartilage. But if these mandibles were articulated with a quadrate they should show some indication of it at their posterior end. If the mandible, with the strong action that must have been present, as evidenced from the great marks of the shear, were pulled against the quadrate by the usual adductor muscles of the Pisces, it is reasonable to suppose that instead of being blade-like the arthrodiran mandible would show the characteristic round- ing and blunting that comes with this kind of strain, as is shown in every mandible of Pisces where there is strong pressure in the back part of the mandible. The reconstruction of the musculature of Dinichthys mandibles, as shown in Plate XI, is worked out from a mechanical point of view, as it appeared to be impossible to adapt the ordinary piscine musculature to the arthrodiran jaws. In this reconstruction it is considered that there must have been a synchronous movement of the skull and mandibles, and the musculature is figured out on this basis. From the peculiar construc- tion of the head, it is inferred that Dinichthys and its allies are the end members of a group that moved the head and had the jaws more or less fixed. The most efficient mechanical construction seemed to require that the inner face of the mandible should be connected by ligament or muscle with the “clavicular element,” which extends forward on the inside of the mandible. If the attachment at this place were by ligament and fascia and the posterior end were appressed to the inner:side of the cheek plate or to some other plate in this region and worked as the scapula works on the body of a mammal, we would have the movement desired, as the rais- ing of the head would aid in raising the back part and lowering the front part of the mandible, while lowering the head would close it. The mech- anism of this part must have been very perfect, for the shear is always in one plane, with no rounding of the edges. On the inner side of the mandible at the anterior end are depressions that show where the mandi- bles were fastened by strong ligaments. In conclusion, the evidence gained from a study of the jaw mechanism of Dinichthys seems to favor the conclusion which has been advocated by many writers, especially Dean and Hussakof, that the Arthrodira are related by common origin with the Antiarchi. 128° ANNALS NEW YORK ACADEMY OF SCIENCES ERYOPS Plate XII, Fig. 1 The massive, frog-like skull of Hryops, a Permian stegoceph, is restored with the anuran type of musculature, though some modifications have been made because of the changes that have taken place in the anuran skull. The skulls of the stegocephalians and of the Anura are strikingly similar in general pattern; that of Hryops with the dermal roofing bones covering the whole skull; that of the Anura with these bones modified, partly eliminated, and all more or less sunken beneath the skin. The large palatine vacuity is similar in both. Gregory has suggested that the ancestor of the Anura was an animal much like Hryops, but that through the changes of the geologic ages the anuran skull became simplified, specialized, and the dermal temporal covering became fenestrated, partly as a result of the action of the muscles. The pterygoid region has changed slightly and has lost the flange that in Hryops projects down in a very, reptilian-like manner. The mandibles are quite similar, although Hryops did not have the backward extension of the articular for the insertion of the depressor mandibule as in the frog, and the frog has lost the promi- nent suprameckelian fossa in the mandible that is so prominent in Hryops. In the Anura the muscles are all very far back on the skull, and we may assume from the Hryops skull that its muscles had a similar position, except that to make the jaw stable it should have had an anterior ptery- goid muscle on the floor of the downwardly projecting pterygoid process. The loss of the anterior pterygoid muscle in the Anura is a peculiar spe- cialization which, very probably, had not been attained by Hryops. The restoration of Hryops gives the following muscles: MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Capiti-mandibularis superficialis (C. m. s.). Capiti-mandibularis medius (C. m. m.). Capiti-mandibularis profundus (C. m. p.). Pterygoideus anterior. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Capiti-mandtbularis superficialis (C. m. s.).—The masseter element would occupy the posterior part of the skull in the space under the ADAMS, PHYLOGENY OF THE JAW MUSCLES 129 squamosal. It would probably have its origin on the inner side of the squamosal and quadratojugal, with a few fibers running to the quadrate and extending ventrally ; it would be inserted on the borders of the supra- meckelian fossa of the mandible. It is on the outside of.the mandible in the Anura; but from the shape of the skull and the mandible there is no chance for it to be inserted there in Hryops. The muscle is split in the Anura and so the masseter of Hryops might have had two parts, the smaller one posterior, in the region of the small quadrate. Capiti-mandibularis medius (C. m. m.).—This temporal slip of the adductor mass would be under the superficial portion and over the ptery- goid muscle. It would have its origin on the inner side of the parietal, with perhaps a slight attachment on the postfrontal. It would be inserted in the suprameckelian fossa. The muscle could extend quite far in the parietal region, taking hold under the skull roof. Possibly the deep part of this mass may have had a separate slip, corresponding to the capiti- mandibularis profundus or “pterygoideus externus” of reptiles. Pterygoideus anterior (Pt. a.).—The pterygoid muscle of Hryops was probably not homologous with the so-called “pterygoid” of the frog, but was more probably homologous with the anterior pterygoid muscle of primitive reptiles. The pterygoid bone is quite different from that of Anura, in that it has a descending flange, much like that of the Croco- dilia, that fits snugly along the inside of the mandible and serves as a guide for it. As this flange in the reptiles is functionally connected with the anterior pterygoid, it seems probable that Hryops had an anterior pterygoid muscle that extended along the pterygoid bone as far as the orbit. A pterygoid muscle is needed here for mechanical reasons, as from the teeth one would judge that the jaw was used differently from that of Anura, and there is need of a muscle here to oppose the pull of the temporal muscles, which would tend to pull the symphysis apart. Thus a pterygoid in this region would steady the jaw and pull the jaw forward against the other muscles. It would have to be inserted in the suprameckelian fossa, possibly extending to the back part. Capiti-mandibularis profundus (C. m. p.).—There is a strong possi- bility that there was a deep slip of the adductor mass, deep under the muscles, that would correspond to pterygoideus posterior of the reptiles. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule.—tThe articular of Hryops does not have the posterior process and the muscle must have been inserted on the under side of the articular. In some American Museum specimens the mandible 130 ANNALS NEW YORK ACADEMY OF SCIENCES seems to show a place where the depressor could have been attached. The origin of the depressor would have been on the squamosal, alongside the otic notch, since in the Anura the origin is on the posterior limb of the squamosal and on the tympanic annulus. The Anura have a second part of the depressor arising from the dorsal fascia, and Hryops also could well have had this second part of the depressor. From the inferred arrangement of the muscles in Hryops, perhaps some explanation may be given of the changes and losses that have taken place in the anuran skull. First, the capiti-mandibularis medius was no doubt attached to the parietal region and the capiti-mandibularis super- ficialis to the squamosal. 'T’o account for the open condition of the tem- poral roof in the Anura and for the loss of the tabulare, supratemporal, squamosal, postfrontal and postorbital, we may adopt the hypothesis that these muscles were pulling against one another; that the region between them gave way and made breaks and openings which did not exist in the primitive form with its unbroken temporal covering. The region be- tween the parietal and the squamosal would lie between the pulls of these muscles and the first break would appear here. The disappearance of the dermosupraoccipitals, tabulars and supratemporals was probably cor- related with the opening out of the temporal region and with the exten- sion of the temporal muscles up on to the top of the skull. LABIDOSAURUS Plate XII, Figs. 2, 3, 4 - This primitive cotylosaur shows the covered or roofed temporal region, which it has inherited from the Stegocephala and from such fishes as Osteolepis, Polypterus and Amia, in which the dermal bones are still in their primitive position in the skin and not sunken below it. The quad- rate is fixed, so that in that region there is no movement. The stout teeth demand strong jaw muscles and there is ample room for a large capiti-mandibularis beneath the temporal roof. The massive lower jaw with its large suprameckelian fossa also requires large muscles. The pterygoid region and the base of the brain case are essentially similar to those of Sphenodon and imply a corresponding similarity in the pterygoid muscles. MUSOLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY Y,) Capiti-mandibularis superficialis (C. m. s.). Capiti-mandibularis medius (C. m. m.). ADAMS, PHYLOGENY OF THE JAW MUSCLES 131 Capiti-mandibularis profundus (C. m. p.). Pterygoideus anterior (Pt. a.). MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Capiti-mandibularis superficialis (C. m. s.).—This slip of the capiti- mandibularis would cover the deeper fibers and arise from the quadrate, squamosal and jugal and be inserted with the medius in the suprameck- elian fossa. Capiti-mandibularts medius (C. m. m.).—This slip would arise on the upper part of the skull and be attached to the parietal, squamosal, and perahps to some of the bones of the otic region. It would join the rest of the capiti-mandibularis in its insertion. Capiti-mandibularis profundus (C.m. p.).—This deep slip would arise on the alisphenoid and outer face of the pterygoid and be inserted with the rest of the mass on the mandible. The whole capiti-mandibularis mass would probably be inserted in the suprameckelian fossa. It would be attached to the bones surrounding the fossa and extend down into it, after the manner of other reptiles, where the whole insertion of the capiti- mandibularis is on the inside of the mandible. Pterygoideus anterior (Pt. a.)—This muscle was no doubt strongly developed as in all typical reptiles. It arose on the under side of the pterygoid and might have extended over the upper face of the pterygoid region as in Chelydra. The form of the articular shows plainly that the muscle must have been inserted on the ventral side of the articular, for there is no evidence that it extended more than slightly into the outer face of the bone. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule (D. m.).—This muscle was no doubt arranged as in other reptiles. It arose on the parietal and extended around the squamosal to be inserted on the upper face of the retroarticular process of the articular, which plainly shows the marks of the insertion. 132 ANNALS NEW YORK ACADEMY OF SCIENCES TYRANNOSAURUS Plate XIII, Fig. 1 The reconstruction of this form was attempted after some comparative study of types like Alligator, Chelydra, Aves and Huparkerwa (Fig. 5). The skull in Tyrannosaurus is secondarily monimostylic, as the quadrates and the upper jaws were less movable than in the more primitive Allo- FIGURE 5 Skull of a pseudosuchian, Huparkeria capensis. After Broom The borders of the large preorbital fenestra may serve for the attachment of the anterior part of the pterygoideus anterior muscle. Around the bony margin of the supratemporal fenestra arose the capiti-mandibularis. Both the supra- and the lateral temporal fenestre gave room for the expansion of the capiti-mandibularis, while the lateral fenestra of the mandible served a like function for the lower end of the same muscle. _gaurus. The monimostylic type is quite stable in its musculature and the reason for this is evident, as the complicated musculature needed for the movable quadrate and pterygoid is lost when the bones become fixed. Tyrannosaurus was a huge carnivorous type with massive skull and jaws; thus the musculature must have been very heavy. ADAMS, PHYLOGENY OF THE JAW MUSCLES 133 MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YV,) Capiti-mandibularis (with three unseparated slips). (a) Capiti-mandibularis superficialis. (6) Capiti-mandibularis medius. (c) Capiti-mandibularis profundus. -Pterygoideus anterior. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY YI!) Depressor mandibule. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY V,) Capiti-mandibularis.—This muscle is considered to have three slips, designated as superficialis, medius and profundus. They are not com- petely separated in the Reptilia. The temporal fenestre show that this muscle had retained its freedom of movement, which it had inherited from some remote aétosaur-like ancestor. There is a long fenestra under the eye, a lateral temporal and a supratemporal fenestra. The capiti- mandibularis would probably conform to the Alligator or Chelydra type. The presence of the supratemporal fenestra means that the temporal or medius slip extended through and was attached to the parietal crest. Thus the medtus slip probably arose on the parietal, extended through the supratemporal fenestra and under the superficial slip to be inserted on the coronoid or in the suprameckelian fossa which is large. The superficialis slip would have fibers extending posteriorly over the rest of the mass. This slip would arise on the squamosal, quadratojugal and be inserted along the upper edge of the mandible and in the suprameckelian fossa. In a few forms this muscle is partly inserted on the outside of the mandible, but the outside insertion is small in typical reptiles. A deep slip might have been present, representing the capiti-mandibularis pro- fundus. Pterygoideus anterior—The insertion of this muscle is plainly indi- cated in the mandible of specimen No. 5027, American Museum, which shows the place where the anterior pterygoid was wrapped around the posterior end of the jaw as in typical reptiles. The muscle probably arose in the space below and in front of the orbits and above the palatines and pterygoid, as in Alligator. The existence of antorbital fenestrae was held ‘by Dollo and by Gregory and Adams (1915) to be correlated with the an- terior extension of the anterior pterygoid muscle—a view adopted here. 134 ANNALS NEW YORK ACADEMY OF SCIENCES MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) This muscle is constant in the Reptilia and its insertion is evident on the specimen No. 5027, American Museum. In many reptiles where the back part of the skull is not greatly modified its origin is on the parietal, but here it seems to have been on the paroccipital. The muscle arose on the ventral end of the paroccipitals, the ventral ends of which are rough- ened for a muscle insertion. Its insertion on the mandible was on the articular, posterior to the articulating surface, where there is a depression similar to that seen in most reptiles. CYNOGNATHUS Plate XIII, Figs. 2-5 The skull is reptilian as a whole, but parts of it very plainly show the mammalian characters, especially the squamosal, the jugal, the dentition and the basicranial region. The quadrate is reduced. The jaw, although reptilian, is of a type that foreshadows that of mammals. The dentary had enlarged from the primitively slender dentary of the early reptiles until it was the most important part of the mandible and must have car- ried the greater part of the musculature. The coronoid process of the dentary is large and ascends far into the temporal fossa. The angle of the dentary is developing and shows plainly. The posterior part of the jaw, consisting of the articular and other elements, is becoming small and is so loosely attached to the dentary that in fossil specimens it is usually missing or found separate from the skull. The old reptilian articulation with the skull had become reduced, but was still functional. Although the new articulation with the jaw had not yet been formed, I infer, from the shape of the temporal fossa and from the direction of the muscles, that the jaw was pulled not directly against the quadrate but toward a point above it on the squamosal. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY Y,) Capiti-mandibularis. (a) Capiti-mandibularis superficialis. (b) Capiti-mandibularis medius. (c) Capiti-mandibularis profundus. Pterygoideus anterior. ADAMS, PHYLOGENY OF THE JAW MUSCLES “Fae MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule. MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP (INNERVATED BY YJV,) Capitt-mandibularis—In Cynognathus this mass of muscle, which is the reptilian muscle of the same name, must have been well subdivided ; thus there was probably a large temporalis or medius slip filling the large temporal fossa and a superficial or masseter slip arising along the zygo- matic arch, both outside and inside, both muscles being attached on the large dentary. The large carnivorous jaws of this form indicate a corre- spondingly powerful muscle which not only filled the temporal fossa but also must have been attached to the outside of the zygomatic arch. The attachment must have been on the ascending process of the dentary, for the posterior bones of the jaw are too small. Watson (1912, p. 581) says: It is a remarkable fact that in Cynodonts increasing size of the dentary and of the masticatory muscles, which in Cynognathus must be inserted on it, is correlated with a reduction and weakening of the back part of the jaw, which alone articulates with the skull; not only are the actual bones small, but their attachment to the dentary is weak; they merely rest in the groove in that bone and are often displaced in the fossil skulls. As the ascending process of the dentary affords ample space, the capiti- mandibularis must have been attached chiefly to this bone, as in mammals. (a) Capiti-mandibularis superficialis—On the outside of the dentary there is a large fossa for the masseter, which must also have been large to match the large temporal mass. It probably had a hold on the inner and outer side of the zygomatic arch, extending forward to the large anterior tubercle on the lower border of the zygoma. The attachment is probably in the depression on the outside of the dentary. From the condition in other reptiles, this superficial slip could extend partly over the rest of the mass and be connected with the fascia of that region. As mentioned before, the pull of these muscles would tend to pull the jaw upwards against the squamosal and not so much against the quadrate. This gave the posterior part of the jaw the opportunity to complete its separation from the dentary in some more advanced form of theriodont and to enter on its new mammalian function in connection with the middle ear. (b) Capiti-mandibularis medius——This part of the temporal mass would fill the temporal fossa and be inserted on the inner and outer sides of the dentary. 136 ANNALS NEW YORK ACADEMY OF SCIENCES (c) Capiti-mandtbularis profundus.—This deep slip must have taken its origin on the inner side of the temporal mass and have been inserted on the ascending process of the dentary. Pterygoideus anterior—To counterbalance the pull of the capiti-man- dibularis mass the anterior pterygoids must have played an important part. The ascending process of the pterygoid is quite large, thus giving an at- tachment for large pterygoids. There is no need for the complex mus- culature of the type found in streptostylic reptiles, so it was probably more of the chelonian or rhynchocephalian type. The pterygoid bones of Cynognathus are bowed inward to the mid line, covering the primary skull base and forming on-each side an extended longitudinal fossa for the origin of the anterior pterygoid muscle. Although the articular, pre- articular and angular bones are small, they seem sufficiently large for the insertion of the anterior pterygoid in the normal place at the back part of the jaw. The insertion of this muscle in all recent reptiles is at or near the rear end of the jaw, and in view of the general fact that inser- tion areas are less variable than origin areas, there seems no reason for regarding Cynognathus as having an exceptional insertion of the anterior pterygoid. The pull of the anterior pterygoid muscle would counter- balance that of the capiti-mandibularis mass and take some of the strain off the weak quadrate articulation. The dentary, imbedded in the tem- poral mass, would thus act as a cushion and the action of the jaw would be the same as though a strong articulation were present. That this action of the jaw was effective is shown by the robust character of the teeth and jaw. If Cynognathus had relied only upon the old articulation by way of the quadrate and articular, a bite on a piece of bone might have dislocated the jaw. As the dentition is carnivorous, the jaws did not have much lateral motion. The reason Cynognathus had a large ascend- ing ramus of the dentary is that it was derived from therocephalians and ultimately from primitive Theromorpha, in which the coronoid bone was functionally replaced by an obliquely ascending process of the dentary. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule.—This muscle was in its usual position, as the posterior end of the mandible shows the insertion. In all reptiles there is a remnant of the C,md of Ruge, and from this the mammalian digas- tric was probably derived. With the loss of the posterior end of the rep- tilian jaw the depressor mandibule of these forms would disappear and a new digastric would be formed from this sheet of muscle that has per- sisted from the fish stage. The long ventral muscles of the throat could — ADAMS, PHYLOGENY OF THE JAW MUSCLES 137 give much aid in lowering the mandible. Watson (1912, pp. 581-582) says: As it is impossible that a muscle should increase while its point of attach- ment is degenerating, it appears probable that the pterygoid muscles were mainly inserted onto the postero-inferior angle: of the dentary, which is thick- ened. Thus inserted, these muscles, while tending to close the mouth, would produce stresses in the hinder part of the jaw, in the opposite direction to those induced by the masseter and temporal muscles, in this way permitting the reduction of the hinder part of the jaw which we actually see. The fact that in higher Cynodonts all the masticatory muscles have their attachments on the dentary renders the freeing of the articular and quadrate demanded by the quadrate-incus theory of the mammalian ossicula auditus much more understandable. It would seem that Watson’s hypothesis that all of the muscles were on the dentary might be questioned, for the cast of the skull of Cynognathus shows plainly the insertion of the depressor mandibule on the posterior end of the articular, while the insertion of the anterior pterygoid seems to have been in the usual position, wrapping around the end of the man- dible as in other reptiles. This last muscle may have been reduced, but its insertion areas on the articular and prearticular seem evident. HOMOLOGIES OF THE JAW MUSCLES IN VERTEBRATES (Tables I-V) INTRODUCTION The first attempts to homologize the jaw muscles in the different groups of vertebrates were based purely upon similarities of function and posi- tion ; and while the work was useful and gave a start in the right direc- tion, it was not altogether reliable. The older writers quickly took up the innervation, as its importance in comparative anatomy became known, and applied it to the determination of the muscles. Thus a much more certain classification arose. Most of the work has been on restricted groups. Vetter in his works on the elasmobranchs and other fishes gave for the muscles of these groups the names that are still used. He divided the muscles up into groups according to their innervation and position and gave the best basis for the classification of the piscine musculature. One of the few papers dealing with the entire vertebrate group is a dissertation by Dr. Ernst Teutleben, published in 1874 under the title, Ueber Kaumuskeln und Kaumechanismus bei den Wirbelthiere. He ex- amined a series of vertebrates and gave a very good description, for the 138 ANNALS NEW YORK ACADEMY OF SCIENCES time, of the jaw muscles in some of the common vertebrates; he also made some observations on the mechanics of the jaw action. He studied the following forms: Dog, horse, sheep, porpoise, bird, Crotalus durissus, alligator, frog, pike and whiting. He failed to differentiate many of the muscles and made no mention of innervation, which is one of the chief criteria used at the present time. The names applied were based upon the origin and insertion of the muscles. He applied this principle to the different classes and gave the muscles names. He did not attempt homol- ogies, except as based upon similar function. He misinterpreted the detrahens mandibule of Ornithorhynchus, as all the others had done until the neurology was worked out by later workers. The greatest stimulation to the work was given by the researches of Ruge on the facialis nerve. He studied this throughout the vertebrates from the elasmobranchs to mammals and gave a reliable basis for the determination of the muscles of this group. Schulman, in his work on the trigeminus musculature of the monotremes, cleared up some of the puzzles that this aberrant group present. Lubosch, Firbringer and others have added much to this work, so that the comparative anatomist now has extensive material for comparison. Gaupp in his work on Reichert’s theory of the origin of the auditory ossicles and Versluys in his studies on the auditory organs in reptiles have worked in this rich field and have given the material a definite meaning, especially in some of the trouble- some problems relating to the changes that took place in the shifting of the bones and muscles, when reptiles of some sort were changed into mammals. Many other investigations have given much information on the muscu- lature of special forms of vertebrates. Chaine, Rouviere, Bijvoet, Toldt, Parsons and others have collected the necessary data on the digastric muscle and have given very full accounts of the condition of this muscle in the mammals. Toldt, in his paper on the jaw articulation and its problems, gives us a basis for the classification of the types of vertebrate jaws, of their articulations and of the correlated types of musculature. Apparently the present work is the first to give a general illustrated re- view of the jaw muscles of vertebrates and to apply this knowledge to an interpretation of the skull structure of recent and fossil types. The study of 26 different forms, representing the classes Pisces, Am- phibia, Reptilia, Aves and Mammalia, has demonstrated that the muscle masses in general are severally homologous from the Pisces to Mammalia, and that they may be grouped into two great systems: First, the muscles innervated by the ramus mandibularis trigemini V;, and, second, the muscles innervated by the facial nerve (VII). ‘There is a sharp line ADAMS, PHYLOGENY OF THE JAW MUSCLES 139 between these muscular systems and their general position has been the same throughout. The trigeminus innervates the muscles of mastication that lie in front of the quadrate, while the facialis innervates the muscles behind the quadrate and those of the hyoid region. These regions in the mammals overlap on the surface, for the reptilian sphincter colli has crept forward over the deeper muscles of the trigeminus and has formed the mimetic muscles of the face, so that while the deep muscles, anterior to the hyoid arch, are innervated by the trigeminus the superficial muscles are innervated by the facialis. This is an example of the faithfulness with which the nerves follow the muscles in their migration (Ruge, 1897). Starting with the elasmobranchs, we find the adductor mandibule muscles, which are undifferentiated masses, derived from the pro-branchial muscles before the anterior branchial arches were transformed into jaws. The adductors are not separated into special muscles, but represent the “mother mass” of the chief jaw-muscles of the V, group in all the higher classes of vertebrates. A depressor mandibule is not differentiated in the elasmobranchs or in the other classes of Pisces, but is represented by the second dorsal superficial constrictor throughout this group, a true depressor first appearing in the Amphibia. In the development of the Amphibia from some of the Pisces the jaw musculature was carried over in its general plan, but the muscle masses took on the peculiar modifications needed in each group. We may con- ceive that these “mother masses” C, and C, became differentiated in many ways throughout the different classes of vertebrates, and that various slips were given off from these masses which served their purpose and the needs of the animal, only to be dropped in the future development, while new slips arose in the higher forms. We may further conceive that these mother masses were innervated by the nerves V, and VII, and that in the first stages of the origin of a new muscle slip there was a mere branch- ing of the nerve into small twigs; in this stage there was no differentiation into special nerves and no division of the muscles into separate slips, but merely partially separated portions with the nerve twigs following and gradually becoming more differentiated, as conditions demanded further separation. Finally, when these slips were separated off from the main mass, the nerve twig became a branch, and the muscle, having lost all connection with the fibers of the parent mass, might be called a separate muscle. This is my conception of the origin of the special muscles in the different classes, and with this view the precise homology, except within the class, is sometimes doubtful, unless very primitive or annectent forms between widely separate groups are available for study. 140 ANNALS NEW YORK ACADEMY OF SCIENCES This separation of the muscle slips from the mother mass may be shown in embryology; for the muscle groups start as undifferentiated masses and then become divided into the different slips. Lubosch (1913) de- scribes the separation from the “temporal mass” of a slip which becomes the “pterygoid” of the urodele. This splitting of the muscle is quite definitely known, and in this paper I have made frequent use of this fact in endeavoring to determine the homologies of the different groups and in reconstructing the muscular systems in extinct forms. (See chapter on reconstructions. ) Some individual muscles may, however, be followed through all the classes of vertebrates. If the history of a bone has been traced from the Pisces to the Mammalia, there is no reason for assuming that the muscles associated with it have changed, provided that they are present in all of the classes and have retained their origin, insertion and to a certain ex- tent their function. Perhaps the hyomandibular (=—stapes), the pre- opercular (= squamosal), and other bones whose history is pretty well known, might be considered as having taken their muscles with them throughout the evolutionary changes from the fishes to mammals, if there is no mechanical or other reason for the dropping of the old and develop- ment of new muscle slips. Muscles are pliable tissues having the power of changing, either by shifting their origin or, if there is no demand for their service, by dropping out. Vestigial muscles found in each of the classes have been carried over from an earlier class and have lost their usefulness and atrophied. A long list of such muscles might be com- piled from the Mammalia or from any class. The vestigial muscles of the ears in Homo, carried over from the simian stage, vestigial muscles in birds, carried over from the Reptilia, the vestiges of the levator arcus palatini in Cryptobranchus and Amphiuma, carried over from the Pisces (Lubosch, 1913, p. 71), the “adductor maxille” in Cryptobranchus from the Pisces, are all vestigial and more or less functionless muscles carried over from one class to another. Homo LoGy OF THE JAW MUSCLES IN THE PISCES (Table I) The primary division of the musculature may be made with the inner- vation as a guide, as there is a natural grouping of the muscles of the head into two systems—the muscles innervated by the fifth or trigeminus and those innervated by the seventh or facialis nerve. The muscles also divide into the same two divisions if we group them first as muscles an- terior to the quadrate region and secondly as those posterior to it. The ADAMS, PHYLOGENY OF THE JAW MUSCLES 141 exceptions to this grouping are the mimetic muscles of the face in mam- mals, which represent the muscles from the second constrictor, innervated by the facialis, that have extended over the face and taken their nerves with them. If we assume that the jaw and hyoid elements represent the first two visceral arches that have changed their function in some pregnathostome stage, it is also fair to assume that the muscles went with them, and that the jaw muscles represent the much divided and specialized constrictors and adductors of primitive branchial arches. Vetter’s analysis of the muscles of the visceral arches appears to hold good at the present day. He held that the adductor mass of the jaws of fishes was homologous with the “adductores arcuum visceralium,” which were small muscles on the inner side of the branchial arches, “mittlere Beuger der Bogen,” lying between the dorsal constrictors above and the ventral constrictors below. As these branchial arches changed into jaws and the development of the hyomandibular, quadrate and opercular elements proceeded, the con- strictor and adductor muscles, which were already in position, would re- quire but little change to take on new functions as jaw and opercular muscles. Accordingly, the constrictors of the pre-gnathostomes may be regarded as the primitive head muscles. In the elasmobranchs the con- strictor became divided into different sections, so that there were dorsal, median and ventral sections, which were either further differentiated to be used as needed or held in reserve for future changes, as in the case of the digastric muscle. This is represented in the elasmobranchs (Ruge, 1897) by the undifferentiated second constrictor, which retains its con- strictor-like form until it becomes specialized in the amphibians into a definite muscle. Throughout the gnathostomes we find muscle masses that may be ho- mologized, but the homology of the separate slips is often questionable. In this paper the attempt is made to work out the homology of the main muscle masses (““Mother” masses) first and then, if possible, to point out the homologies of the separate slips of each mass, especially in the mem- bers of the same class and where possible between classes. To homologize the separate slips through the different classes means that one must know the ancestry and be able to demonstrate the movements and changes in the osteology, so that in default of such knowledge the result is often ques- tionable. The muscles of the piscine head may be divided as follows (the related muscles are placed together) : 142 ANNALS NEW YORK ACADEMY OF SCIENCES MUSCLES INNERVATED BY THE TRIGEMINUS NERVE Levator maxille superioris. Levator arcus palatini. Protractor hyomandibularis. Dilator operculi. Adductor mandibule (often divided in the Pisces). MUSCLES INNERVATED BY THE FACIALIS NERVE Adductor hyomandibularis. Levator operculi. Adductor operculi. MUSCLES INNERVATED BY THE TRIGEMINUS NERVE Levator maxille superioris (Adductor 8 Vetter). Levator arcus palatum 1-5 McMurrich.—These are a series of muscles that extend from the under side of the skull to the maxilla. They vary in number in the Pisces from one to four or five. In Acanthias they arise in a mass anterior to the spiracle and the remains of the first constrictor dorsalis superficialis and extend to the maxille; here they form a single muscle. In Amia they are partly anterior to the eyes. They probably represent the dorsal part of the first constrictor superficialis and function in the movement of the maxille. In the teleosts they lose their impor- tance and disappear, except for a few tendinous remains, while the levator arcus palatini becomes more important and usurps the place of the lev- ators of the maxille. Levator arcus palatint.—This muscle raises the bones of the palatine region and is of great importance in the fishes where this region is de- veloped. In the elasmobranchs it is not needed, but is perhaps repre- sented by the remains of the first constrictor, just anterior to the spiracle. It is prominent in most teleosts and Holostei, but drops out where this region becomes fixed. This muscle is closely related to the protractor hyomandibularis and the dilator operculi. McMurrich (1885) calls the protractor hyomandibularis “levator arcus palatini” in Amia. They are | often close together and sometimes not entirely separated as in Amita. Protractor hyomandibularis—This draws the hyomandibular forward. It probably represents a part of the first constrictor. It is always closely connected with the levator arcus palatini. It varies in size, being very large in Acipenser and Polyodon, of good size in the teleosts, and absent in the dipnoans, where the hyomandibular is rudimentary or absent. Dilator operculi.—This is the posterior slip of the first constrictor. It pulls the operculum forward and slightly raises it. It is closely con- ADAMS, PHYLOGENY OF THE JAW MUSCLES 143 nected with the protractor operculi, always lying just behind it, extend- ing over the groove for it in the hyomandibular just above the preoper- cular. Often the preopercular also shows where the muscle extends over the upper end of it. Practically every skull studied showed this muscle area, so that it is easily demonstrated on any skull in the teleosts or other fish group. It is inserted on the under side of the opercular in most forms. Adductor mandibule.—This is considered as the mother mass of the chief jaw muscles throughout the vertebrates. In the elasmobranchs it is almost a single mass, partially subdivided in the rest of the fishes and reptiles and completely divided in the Amphibia and Mammalia. It is innervated by the third branch of the trigeminus and represents a part of the first constrictor with its nerve. The condition in the elasmo- branchs is usually as a single mass, although the fibers cross each other and do not always extend in the same direction, but there is no definite separation in those studied and none described in the literature on other forms. ‘There is a tendency throughout the remaining Pisces for this mass to be partially divided. In general this muscle may be divided into two parts—a superficial part that extends across the other fibers and is attached in the quadrate and squamosal region and a deeper set of fibers which extend up to the postfrontal and parietal region. No attempt is made in this paper to homologize these portions, although they are con- stant and seen to be starting a condition that eventually may have re- sulted in the separation of these slips from the mother mass. The sim- plest adductor mandibule is found in Acanthias and the most complex in Amia and Hsoz, although the division is never complete. Amaia, Pali- nurichthys and many other forms show a peculiar specialization, where a part of the adductor (Adm*) extends into the suprameckelian fossa and excavates the dentary, so that the bone is completely filled with this part of the muscle. MUSCLES INNERVATED BY THE FACIALIS NERVE This series of three muscles is concerned with the movement of the opercular and hyomandibular bones. They represent a part of the second dorsal constrictor and show the characteristic innervation of this mass. Adductor hyomandibularis.—This is a deep muscle which arises on the . posterior part of the skull in the otic region, anterior to the other two. It is usually small and short and is not easily seen unless the opercular bones are removed. It opposes the protractor hyomandibularis and raises the hyomandibular bone. It is attached to the inner side or to the pos- terior border. It is shown in Acipenser, Polyodon and Polypterus. 144. ANNALS NEW YORK ACADEMY OF SCIENCES Adductor opercult and levator operculi.—These are closely associated. Both arise on the posterior part of the skull in the otic region and are inserted on the inner side of the opercular bone. Often one of them is absent or perhaps they are not differentiated. They are present in almost all the Pisces with the exception of elasmobranchs. They are small in the dipnoans. Homonocy oF THE JAW MUSCLES IN THE AMPHIBIA (Table IT) There is quite a difference between the muscles of the Pisces and those of the Amphibia, for in the latter muscles masses have become more spe- cialized by a splitting off of the different slips, so that they may be called separate muscles. Some of these divisions were suggested in the Pisces by the direction of the fibers and by differences in the origin and inser- tion, but they remained a part of the parent mass, as they do, for the most part, also in the Reptilia. In the Amphibia the muscles of the anterior part of the piscine head have disappeared, being represented by vestiges only. Lubosch (1913, p. 71) says: Bisher unbekannte Muskelrudimente wurden gefunden bei Amphiuma und Cryptobranchus. (1) Hin M. levator arcus palatini bei Amphiuma and Cryptobranchus, von der knorpligen Nasseskapsel und (Amphiuma) der vertikalen Lamelle des Frontale (Wiedersheim) entsprigend und zur Membrana pterygomaxillaris zeihend. (2) Hin M. adductor maxille bei Cryptobranchus vom vorderen Rand des kn6chernen Pterygoids und dem knorpligen Proc. pterygoideus quadrati ent- springend und in der Nihe des Maxillare in der Membrana pterygo-maxillaris endend. Beide Muskeln werden mit feinen Aestchen aus demselben Nerven versehen, whelcher auch die Mm. pterygoidei versorst. The great changes in the skull of the Amphibia account for the reduc- tion and dropping out of several of these typical piscine muscles. There is no need for the levator maxille superioris and the levator arcus pala- tini, as the parts controlled by these muscles are fixed. The new form of the bones demand a different musculature and the loss of others. The preopercular, symplectic, hyomandibular, opercular, inter- and sub-oper- cular and. several of the bones of the skull.and maxillary region have | either been lost or changed their functions, so that new muscles are needed. If the hyomandibular is considered to be the stapes of the higher forms, it seems to have discarded its original musculature in the transfor- mation, for there are no muscles in the forms with a stapes that could have been retained from the muscles of the hyomandibular. The two hyomandibular muscles—the protractor (V,) and the levator (VII)— _— ADAMS, PHYLOGENY OF THE JAW MUSCLES 145 could not have been carried through to the Mammalia, or at least there is nothing to show that such was the case, as the new stapedial muscle is regarded as a slip from the C,md or from the reptilian depressor man- dibule. The preoperculum, which is considered to be the squamosal of the forms above the Pisces, retains its old connection with the temporal muscle mass, so that the masseter (or superficial) slip of the urodeles and anurans is still associated with the transformed preoperculum. In the Amphibia the piscine operculum is absent, so that the three muscles attached to it in the Pisces would be lost. The simplest condition of the musculature is found in the urodeles, where the muscles are well separated, but are not so specialized as in the Anura and retain more of their piscine condition. They are divided into slips, three or four in number. ‘These are separate slips that compare with those indicated in the muscles of the reptiles, but are not regarded as fully homologous with them. The superficial slip is the typical mas- seter-like muscle with the same general direction of the fibers and the same relation to the main mass. The deeper muscles of the peculiar “Temporal mass” have a peculiar specialization, in that one slip extends back over the skull and arises no longer on the parietal, but on the neck vertebre, sometimes as far back as the fourth cervical vertebra. (See urodeles.) ‘The anterior temporal, which arises from the side of the skull, behind the eyes, and runs outward and backward to the inner side of the mandible, is apparently comparable to the pterygoideus anterior of rep- tiles. This pterygoideus anterior has separated from the under side of the capiti-mandibularis mass, but does not arise from the pterygoid. The Anura show the highest specialization found in the amphibians, as the muscles are not only divided into slips, but the slips are well sepa- rated, both in their origins and in their insertions on the mandible. The striking thing in connection with the anuran jaw muscles is their con- nection with the auditory region, for the muscles of mastication and some of the neck muscles serve to keep the tympanum stretched taut. The division of the capiti-mandibularis superficialis (masseter) is suggested in the urodeles, where the fibers of the single muscle show an interme- diate condition. The depressor mandibule is the same throughout the group. -It has two slips, one from the skull and one from the dorsal fascia. They represent again the C,md of Ruge, which is the mother mass of this group innervated by the VII nerve. It seems from the innervation, origin and insertion that the individual slips may be homolo- gized throughout the Amphibia, and the homologies as they appear are shown in Table II. 146 ANNALS NEW YORK ACADEMY OF SCIENCES HoOMOLOGIES OF THE JAW MUSCLES IN THE REPTILIA (Table IIT) The jaw muscles of the Reptilia and Aves show the same division into masses as do those of the Pisces and Amphibia. There is the same group- ing of the masses into muscles innervated by V, and by VII and they have the same relative position as in the lower forms. The muscles show more specialization, as there is a higher specialization of the skull in Reptilia and Aves and consequently a more complex musculature. In the reptiles the capiti-mandibularis mass is more homogeneous than in the Amphibia, and while the pterygoid muscles have separated off, the capiti-mandibularis superficialis remains attached. In the birds there is a complete separation of the muscles. The great specialization in the higher or streptostylic reptilian skulls is correlated with the great complexity of the musculature. The Reptiha are divided arbitrarily into two groups according to the fixity or mova- bility of the quadrate; but this is a relative division, for all stages are found between the streptostylic and the monimostylic conditions. The © jaw muscles of the Reptilia may be grouped according to the innervation, as follows: MUSCLES OF THE CAPITI-MANDIBULARIS OR TEMPORAL GROUP (INNERVATED BY Y,) Capiti-mandibularis. (a) Superficial slip (not separate). Masseter. (b) Medius slip (not separate). Temporal. (c) Profundus slip (not separate). Deep layer. (d) Cranio-pterygoid. Pterygoideus anterior. Pterygoideus posterior. MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP (INNERVATED BY VII) Depressor mandibule. MUSCLES OF THE CAPITI-MANDIBULARIS GROUP (INNERVATED BY YV,) Capiti-mandibularis.—This muscle is not divided into separate muscles, but the conditions suggest the divisions to appear later in the mammal- like reptiles. (a) The outer or superficial slip may apparently be traced from the fish to the mammal. It always arises from the squamosal region ADAMS, PHYLOGENY OF THE JAW MUSCLES 147 and is inserted on the coronoid region of the jaw along with the rest of the mass. (b) The medius slip also is not separate, the fibers being under the superficial slip and extending to the parietal region. (c) The profundus is represented by the deep part of the mass. (d) The cranio- pterygoid muscles are the special muscles developed in the pterygoid re- gion of the streptostylic reptiles and are new developments. Pterygoideus anterior and pterygoideus posterior.—The so-called ptery- goid muscles of reptiles include two quite different groups; the posterior group represents the deepest part of the capiti-mandibularis mass. It is usually named the pterygoideus externus or external pterygoid, but it is probably only partly homologous with the mammalian external pterygoid. I have named it the capiti-mandibularis profundus. It is often sub- divided into two heads, which may be named caput 1 and caput 2. The anterior pterygoid called by Mivart “Internal pterygoid” and in this paper “Pterygoideus anterior’ represents the anterior part of the ad- ductor mass or C,smd of fishes and is foreshadowed in Polypterus. It may be the homolog also of the so-called “temporalis” of urodeles. It is far in front of the “Pterygoideus externus” and runs in the opposite direction, crossing it at a wide angle on its way from the orbital region to the back of the mandible. It is always present in the reptiles and acts. in concert with the capiti-mandibularis mass in closing the jaw. More in detail the action is described in the section on reptiles. MUSCLES OF THE DEPRESSOR GROUP (INNERVATED BY VII) The depressor mandibule acts as the depressor of the mandible. It is constant throughout the Sauropsida. It was retained throughout the series until the mammal was evolved, when probably a new slip was sepa- rated from the mother mass and the new depressor of the mammal was formed. Futamura (1907, p. 570) on comparative and embryological evidence stated that the stapedial muscle of the mammals and man comes from the proximal or upper part of the muscles of the hyoid arch (innervated by VII)—+that is, the mother mass of the depressor mandibule—and that the reptiles also derive their stapedial muscles from the same source. Futamura says: Der M. stapedius stammt von den Muskelfasern die sich vom proximalen Teil der Hyoidmuskulatur nach Gehérknéchelchen begeben: Bei den Reptilien (Krokodil, Lacerta) ist er mehrfach und in seine Funktion auch verschieden von der der Végel und Saéugethiere. Nach Killian finden sich beim Krokodile Ohrmuskeln, die Heber, Herabzieher der Ohrklappe und Spanner des Trommel- 148 ANNALS NEW YORK ACADEMY OF SCIENCES felles sind. Bei der Hidechse konnte ich nur zwei Muskel finden, die sich dem Levator der Ohrklappe und dem Depressor der Ohrklappe und Spanner des Trommelfelles der Krokodile verglichen habe. Bei den V6égeln, Siugethiere und dem Menschen ist der Stapedius einfach, geht beim Vogel an der Columella und bei den Siugethiere an den Steigbiigel. Hier verliert er damit die direkte Beziehung zum Trommelfell und macht auch einen Funktionswechsel durch, auf den ich hier aber nicht niher eingehen will. SUMMARY The relations of the jaw muscles of reptiles and Amphibia are well summarized by Lubosch (1913, pp. 72-73) as follows: | Die Vergleichung mit den Reptilien (verg. die Beschreibungen yon Fischer, d’Alton, Sanders, Mivart, Versluys, Watkinson, Bradley) Der Organization- stypus der Urodelen ist auch heir unverkennbar vorhanden. Die Muskulatur ist zwar miadssiger, aber zweifellos weiniger eingreifend gegliedert als dort. (Bei Krokodilen ist sogar Masseter und Temporalis sehr réduziert.) Der Ramus mandibularis liegt auch hier zwischen Masseter und Temporalis aussen, Pterygoideus innen. Der Pterygoideuskomplex tritt auf als Pterygo-mandib- ularis (Bradley) (homolog dem Pterygoideus posterior der Urodelen) und als ein als, Pterygoideus (Bradley) auch “Pterygoideus internus” bezeichneter Muskel (Homolog dem Pterygoideus anterior der Urodelen) Bei Cheloniern (und Krokodilien . . .) sind alle Hauptteile der Muskulature scharf geson- dert, bei Lacertiliern und Ophidiern scheinen sie nach den Angaben der Liter- ature mehr zusammen-zuhingen. Besondere Eigentiimlichkeiten bietet eine tiefe Masseter-portion dar, in betreff welcher auf die genauere Darstellung verweisen wird. Wichtig is nun vor allem die Differenzierung der motorischen _Trigeminusiste. HomMouoGy OF THE JAW MuscLES IN AVES (Table IIT) The musculature of the jaws in birds has been derived from the rep- tilian position with lttle change. As the bird skull is streptostylic, the reptile most easily compared with it is Varanus and some of the fossil forms as mentioned in the section on Aves. ‘There is a separation of the muscles, so that the capiti-mandibularis is divided into a superficial, a median and deep portion. The deep portion fills its usual place and the superficial has its origin on the squamosal and quadrate. ‘These muscles are opposed by two pterygoid muscles that are homologous with those of — the reptiles. The pterygoideus anterior (pterygoid internus) is the homolog of the muscle of the same name in the Reptilia; it does not wrap around the end of the mandible but is inserted on the inner, posterior face of the mandible as it does in some reptiles—e. g., Chelonia. Pterygoideus pos- ADAMS, PHYLOGENY OF THE JAW MUSCLES 149 terior is the posterior slip from the capiti-mandibularis, which is sepa- rate in birds. It crosses the anterior pterygoid and is the homolog of the muscle of the same name in Reptilia. The depressor mandibule is large and is the homolog of the depressor of the Reptilia. The presence of the stapedial muscle in the Aves shows that in some of the reptiles and Aves the stapes was connected with a part of the de- pressor mandibule. Futamura (1907) has shown that this was true in the embryology of the sparrow and of the duck: Der Stapedius entspringt von der Gehérkapsel und geht zum Columella und zu der medialen Seite der Gehédrgrube. Ein Teil der Muskelfasern scheint mit dem proximalen Abschnitt des Quadratum Beziehung zu haben. In der Sperling der M. stapedius, der aus dem vorher erwiihnten proximalen Teil der Facialismuskulatur entsteht, ist sogar schon ziemlich deutlich differ- enziert. Er liegt an der dorsalen Seite der tibrigen Facialismuskulatur und zieht grosstenteils an der medialen Seite des Facialisstammes nach hinten, medial, und endet dicht an der Carotiswand der Nervus facialis ist bedeutend verlingert. In der Ente M. stapedius, digastricus und stylohyoideus differen- zieren sich aus dem Blasten der post-auricularen Gegend. HoOMOLOGIES OF THE JAW MuscLEs IN MAMMALS (Table IV) The great transformation of the reptilian skull into the mammalian skull has been correlated with equal changes in the jaw muscles. The temporal fosse of mammals have opened out, so that the temporal and masseter muscles extend to the surface of the head and thus gain room and free action for diverse adaptation and for expansion. By the devel- opment of the sagittal and occipital crests the areas for the origin of the temporal and neck muscles are greatly increased. The masseter becomes enlarged and its origin spreads over the zygomatic arch. This specializa- tion of the superficial part of the temporal mass is typically mammalian, as nothing like it is seen in the reptiles. The great changes in the mandible, the reduction of the posterior jaw elements, and the development from them of the malleus and incus have been correlated with an equal transformation of the muscles. The inser- tion of the whole temporal mass has shifted from the coronoid region of the mandible to the dentary, while the external muscle gave rise to both the internal and external muscles of the mammals. The formation of accessory auditory ossicles from the reduced posterior jaw elements gave opportunity to certain of the reptilian muscles to assume new functions. ‘The stapedial muscle, for example, would be homologized with the 150 ANNALS NEW YORK ACADEMY OF SCIENCES upper part of the reptilian depressor mandibule, as it has been shown in the sections on birds and reptiles that the depressor is in the position to gain the relations of the stapedial muscle of the mammals. It hardly seems possible, from the conditions seen in Oynognathus, that the de- pressor mandibule has been carried over from the reptiles as the posterior belly of the mammalian digastric. The most satisfactory conclusion ap- pears to be that a part of the depressor became the stapedial muscle and that the mammalian digastric is a new slip from the second constrictor mass, which was still retained in the reptiles (Ruge). Wilder (1909), in discussing the origin of the stapedius, says: “A portion of the posterior belly, that is, of the second levator, becomes separated from it in the rep- tiles, and follows the stapes into the middle ear, whence it becomes the stapedius muscle, innervated by a special branch of the facialis.” That the stapedius muscle is an ancient muscle appears to be’shown by the great separation of the digastric and stapedial nerves, both of which are branches of nerve VII. In other groups of related muscles the nerves, although branching and becoming more than mere nerve twigs, still indi- cate their relationship by their proximity to each other, as in the case of the subdivisions of the nerve V,, where the muscles that are closely related have their nerves coming off close together. The stapedial nerve comes off at the upper part of the facialis, while the digastric nerve comes off far below it. This seems to help the hypothesis of the derivation of the — stapedial and the wide separation in time from the appearance of the mammalian digastric. Two muscles, the tensor tympani and tensor palati, appear in the mam- mals for the first time. They are innervated by the ramus mandibularis of the trigeminus and, according to Gaupp, their homology may be looked for in one of the pterygoid muscles of the reptiles, namely, the “pterygo- mandibularis” of Bradley, which is the “anterior pterygoid” of the pres- ent work. This muscle is in the position that would permit it to be drawn into the middle ear as the tensor tympani, and it is also in a posi- tion to give rise to the tensor palati. The anterior pterygoid of reptiles is attached to the posterior end of the mandible, and during the change from the reptilian to the mamma- lian condition it could be drawn into the middle ear without much change, as has been shown above. A review of Gaupp’s discussion, however, leaves ~ me in doubt whether these muscles have both come from the reptilian — pterygoideus anterior or from the reptilian external pterygoid or from both. Their connection with the pterygoideus internus of man would indicate their derivation from the deep portion of the capiti-mandibularis of reptiles. The insertion of the tensor tympani on the handle of the — ADAMS, PHYLOGENY OF THE JAW MUSCLES 151 malleus would, on the other hand, indicate relationship with the anterior pterygoid, which in reptiles is inserted gn the back part of the mandible. The topographic relations of the tensor palati suggest one of the cranio- pterygoid muscles of reptiles. The tensor veli palatini (tensor palati) is called by Gaupp the homolog of the reptilian “pterygo-mandibularis” (anterior pterygoid). He points out that Kostanecki (1891) in Didel- phys showed the close relation of tensor tympani and tensor veli palati. Kilhan (1890) also found that the two muscles were joined in the early stages of apes, man, Cheiroptera, etc. In man the two muscles appear at about the fourth month to become separate from the pterygoideus inter- nus. ‘These facts in the embryology would appear to show that tensor tympani and tensor veli palati are phylogenetically related; that they come from the pterygoid musculature of the reptiles, probably from the anterior pterygoid. Their close relations with the mammalian ptery- goideus internus also indicates that they arose from the same region of the temporal mass. This derivation of the tensor tympani from one of the pterygoid muscles seems very plain, for it extends down along the side of the eustachian tube in the mammals and is attached to the handle of the malleus, so that the essential relations are not changed in the transformation of a jaw muscle into an auditory muscle. The mammalian pterygoid muscles may possibly both be derived from the deep part of the capiti-mandibularis mass of reptiles—that is, from the capiti-mandibularis profundus or pterygoideus externus. The changes in the posterior part of the jaw and in the skull would make it almost impossible to derive these from the anterior pterygoid muscles. The diffi- culty in deriving the pterygoid muscles of mammals from the anterior pterygoid muscles of reptiles is that the latter are inserted on the posterior part of the mandible, an element which became vestigial, while the former are inserted wholly on the dentary. A study of the jaws and skull of Cynognathus and the other cynodonts indicates that it would be difficult to conceive clearly the transference of the insertion point of the anterior pterygoid from the angular and prearticular region to the back part of the dentary. On the other hand, the pterygoideus or capiti-mandibularis profundus, which is inserted in the region of the coronoid, is in such a position that the upgrowing, ascending ramus of the dentary might well invade its insertion area. In this way a muscular connection between the _ wall of the cranium and the inner side of the dentary might easily be established. As the reptilian palate and lower jaw became completely transformed, it is to be expected that the characteristically reptilian pterygoideus anterior would degenerate along with the elements on which it was inserted. From the innervation of the mammalian pterygoid 152 ANNALS NEW YORK ACADEMY OF SCIENCES muscles, which is from different parts of the ramus mandibularis, we may assume perhaps that the pterygoideus internus has long been sepa- rated from the temporal mass, and that the pterygoideus externus is the newer muscle that still bears a close relation to the temporal muscle in the mammals; and so far as I have discovered, the pterygoideus externus is present throughout the Mammalia, while the pterygoideus internus, which has been separated from the mass for a longer time, has in some cases (monotremes) disappeared or never developed. Of the pterygoid externus Lubosch (1913, p. 75) writes: Der Pterygoideus externus hat keinfalls seinen Mutterboden in einem der Pterygoideusteile der Urodelen. Die Darstellung von Schulman, dass er einem tiefen Teile des Temporalis nihestehe, lisst sich aus den Verhiltnissen der | Urodelen verstindlich machen, wo der Temporalis geradezu iiberraschende’ Differenzierungen in einzelne Portionen zeigt, so dass sich die Ansicht recht- fertigen lisst, das der Pterygoideus externus in bestimmten Teilen der Tem- poralis-muskulatur der Urodelen enthalten sei. But unless the amphibian ancestry of the Mammalia were accepted, one would question the homology of the mammalian muscles with any- thing found in that group. Of the pterygoideus internus Lubosch (1913, p. 75) writes as follows: Der Pterygoideus internus scheint hingegen alter Besitz der Ahnen der Siiugethiere der sogar seinen Ursprung bewahrt hat. MHinsichtlich seiner In- sertion ist zu errinnern, das schon bei Fischer Ausbreitungen am Dentale bis nach vorn vorkommen (Vetter) Auch er fehlt den Monotremen, so dass hier die gesamte bei Urodelen angelegte tiefe Temporalisschict nicht vorhanden ist, der 3. Ast des Trigeminus also unmittlebar unter der Wangenshleimhaut liegt. Da sich bei Urodelen der Pterygoideus internus aber auf allen Stufen der Emanzipation vom Temporalis zeigt, so lassen sich ausgangszustande auch fiir die Muskulatur der Monotremen mit Wabhrscheinlichkeit feststellen, ohne dass die Frage hier erdtert werden kann. I certainly agree that there is no relation between the muscle of the urodele and the mammal, except in the general scheme of homology of the temporal mass, but the rest is special development in both groups, especially in the pterygoid musculature. Regarding the digastric, it is now generally agreed that it is not the depressor mandibule of the Reptilia, Aves, or Amphibia, but an offshoot- of the same parent mass, namely, the second constrictor, that has been retained throughout the vertebrates and has always supplied the depressor for the mandible, except in the monotremes. : : ADAMS, PHYLOGENY OF THE JAW MUSCLES 153 GENERAL SUMMARY OF HOMOLOGIES AND EVOLUTION OF THE JAW MUSCLES IN THE VERTEBRATES The following conclusions may be regarded as well established: (1) The two chief muscle masses of the jaw, (a) the adductor mass innervated by the ramus mandibularis (V,) and (b) the depressor or digastric mass innervated by the facialis (VII), are homologous through- out the Vertebrata.. (2) The adductor of the Pisces is the mother mass from which the muscles of mastication in front of the quadrate are derived throughout the vertebrates, by the separation of slips of this muscle and by their gradual complete separation in nerve supply through the growth of the originally small twigs into separate nerve branches. In the evolution from fishes this adductor has changed profoundly and much of it has been lost, but the original topographic relations of the muscle remain the same throughout the vertebrates, whether all parts are completely sepa- rated or not. (3) Some of the so-called pterygoid muscles have been developed inde- pendently in the amphibians, reptiles and mammals. The new develop- ments have been slips needed in the movements of the pterygoid region in streptostylic reptiles, and probably a new series of pterygoid muscles for the mammals. (4) The amphibians retain rudiments of the levator arcus palatini of _ the fishes, but these muscles are lost beyond this group. (5) In the streptostylic reptiles the complex pterygoid musculature was developed to meet the needs of the movable quadrate. (6) The complicated musculature of the pterygoid in the streptostylic forms which was developed by the subdivision of the capiti-mandibularis mass into numerous slips. (7) The birds inherit much from the reptiles, and parts of their ptery- goid musculature are undoubtedly homologous with those of reptiles, as follows: Pterygoideus profundus of the birds = capiti-mandibularis profundus in the reptiles. Pterygoideus anterior of the birds = muscle of the same name in the reptiles. The capiti-mandibularis superficialis and capiti-mandibularis medius = subdivided capiti-mandibularis of the reptiles. (8) The tensor tympani and the levator veli palati of mammals ap- pear to represent vestiges of the pterygoideus anterior of reptiles. The tensor tympani took on its modern functions when the back part of the 154 ANNALS NEW YORK ACADEMY OF SCIENCES reptilian jaw gave up its primary function and was taken over into the service of the auditory organs. It retains its old relations with its inser- tion on the handle of the malleus (in reptiles it was inserted on the retro- articular process of the mandible and on the prearticular). The levator veli palatini seems to represent a part of the same pterygoideus anterior that has changed its relation slightly to serve in the region of the mam- malian palate. | (9) The region innervated by the facialis has changed somewhat in the mammals. The depressor mandibule of the reptiles has given rise to the m. stapedius of Be mammals and the rest of the muscle has dis- appeared. (10) The posterior belly of the digastric of mammals appears to be a new development that has come from the remnants of the posterior part of the second constrictor (C,sd) of reptiles. It is thus believed to be a new muscle which has nothing to do with the “Digastric” of the reptiles, although it has the same functions and the same innervation. To this posterior belly has been added or grafted on at the anterior end one of the long ventral V, muscles to make the anterior belly of the mammalian digrastic. 7 (11) The slip that functions as the m. stapedius in mammals appears to have started in the reptiles and has been retained from the depressor mandibule. This muscle, which is connected with the distal end of the stapes in mammals, started in the reptiles and reached its perfected con- dition when it was drawn into the middle ear in the course of the trans- formation of the mammal-like reptiles into the true mammals. As men- tioned above in the sections on birds and reptiles, the future stapedial muscle was in the right position in the reptiles, where the depressor touches the distal end of the stapes, so it is not difficult to imagine how the depressor gave off a slip that became the future stapedius muscle. RELATIONS OF THE JAW-MUSCLES TO THE TEMPORAL FENESTRA oF REPTILES The following from Gregory and Adams (1915) summarizes their observations on the relations of the jaw-muscles to the temporal fenestrae: _ (1) That in primitive vertebrates the chief temporal muscle-mass (adductor mandibule of sharks) was originally covered by = dermal, temporal skull-roof. (2) That in modernized Amphibia and Reptilia, as well as in Aves and Mammalia, one or more slips of the primitive adductor mass had secured additional room for expansion by perforating the temporal roof ADAMS, PHYLOGENY OF THE JAW MUSCLES 155 either at the top or at the sides or in both regions at once; much as in histricomorph rodents, a slip of the masseter has invaded the region of the infraorbital foramen, so that it now extends through a widely open arcade and finds room for expansion on the side of the face. (3) A comparative study of the skull of Tyrannosaurus led to the suspicion that the pre-orbital fenestre of the dinosaurs, phytosaurs, pte- rosaurs, etc., were also functionally connected with the muscles of masti- cation ; but it was realized that proof of this view required a wider study of the jaw-muscles of living reptiles. It was afterwards found that Dollo (1884) had suggested that the pre-orbital fenestree of extinct reptiles were filled by the pterygoid muscles. (4) The inferred conditions of the jaw musculature of Cynognathus are in harmony with the view that in the mammal the back part of the reptilian jaw became transformed into the accessory auditory ossicles. (5) As a working hypothesis, it is assumed that the transformation of certain elements in the temporal and occipital regions of early Tetra- poda was partly conditioned by the stresses induced upon the skull-roof by the jaw and neck muscles. Comparison with lizards, Sphenodon, etc., clearly indicates that the prolongation of the parietal into the postero- external process, joining the true squamosal, was correlated with the squeezing effect of the capiti-mandibularis and depressor mandibule muscles. This may also be responsible for the suppression of the supra- temporal and survival of the squamosal in early reptiles. The shifting of the post-parietals (dermo-supraoccipitals) and tabularia from the dorsal to the posterior aspect of the occiput was no doubt influenced also by the forward growth of the neck muscles upon the occiput. 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S90SIq 94} 2 94} Ul payeljUstOYIp JOU ST} pus Ur poa}eljuslayIp jou S4OSIq IOI1o}ue Sop sojapoiyn bs -lo3A1a}d 10 ssem [viod *pueuUl-1j1deo 94} Jo UOT} ey} Ul o}e1edas jou 3 i 45 -119} 94} jO UOTJ10d 1IO11a}jUe -10d snpunjoid 10 daap snipeut | sijvroysodns VIG Hd NY sorjdol jo snpunjoid oy} Ul pojJues . 8014} jo -91de1 Ajqeqoid SHAW e[nqipueur pug sefosnu [e1} . 101190} snpunyj PeplAIp jou Ajjensn Jossoidaep jo Jed JolJajsod | -UaA SuOo, 9} -U® SNEepIosA19}d 9y} Wo dy -O1d slie[nqipueu-1jideo jynq ‘jUsseid sseur Ssliv[nqipuvuU-1}ideo pue VITILda yy eiqryd Uy 10 Sol} -doil jo iossoid -op 934} jo sO, : soule.l} -OWlOY 94} JON -OUOJ 9} UI Jd90xe yuosoid |*pulzd jodiis mou yuosoid jussoid yussoid s[emueU Ul Juasoid yuaso.id yuosoid jyuasoid VIIVNNV]N DIISBSIC DIISVSIC. ed ‘Ted snui9jUul d snipede}¢ ay} jo ay} Jo Ne i snudojUL snepiosA1o snopioss1a ee ar |. “See eae p Ss nage a J -mA} 10SUdT, | I[OA 10} BAOd'T 2 PI Id Maecenas SNIPS [evroysedng A[[@q 1O1I9}S0g A]J9q Jol10juy (SSVW WOLMNGay Ao IvuxOdWaL) $A AP GALVAMANNT SATOSAW IIA A# GALVAUANNY SATOSOW PE EEN eer 8 rt oe ee Ae ne ae ES Te RS SR eee SE; Res Be ee ee S4SSVTO ALVAEFALAYA AHL NI SHIOSOW MVC AHL AO ADO TONOH—A 318YL 160 ANNALS NEW YORK ACADEMY OF SCIENCES : BIBLIOGRAPHY D’ALTON, E. 1834. 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Zweiter Theil—wWirbel- — thiere, pp. 161-180. 7 STANNIUS, H., and SIEBOLD, C. T. E. von. 1854. Lehrbuch der Vergleichende Anatomie. Zweiter Theil—Wirbel- thiere, pp. 1-128. STRASSER, H. 1908. Lehrbuch der Muskel— und Gelenkmechanik, pp. 475-502. Berlin. ~~ ore ADAMS, PHYLOGENY OF THE JAW MUSCLES 165 TEUTLEBEN, FE. VON. 1874. Ueber Kaumuskeln und Kaumechanismus bei den Wirbelthieren. Arch. f. Naturw., pp. 78-111. TIESING, B. 1895. Hin Beitrag zur Kenntnis der Augen-, Kiefer- und Kiemen muskulatur der Haie und Rochen. Theil 2. Jen. Zeitschr. f. Naturw., N. F., XXX, pp. 75-126. TOLDT, C. 1905. Der Winkelfortsatz des Unterkiefers beim Menchen und bei den Siugetieren und die Beziehungen der Kaumuskeln zu demselben Theil 2. Sitz. d. Kais. Akad. d. Wiss. Wien. Math.-Naturw. K1., CXIV, Abth. 3, pp. 315-476. 1908. Der Vordere Bauch des M. digastricus mandibule und seine Varie taten beim Menchen. Theil II. Sitz. d. Kais. Akad. d. Wiss. Wien. Math.-Naturw. Kl., CX VII, Abth. 3, pp. 229-321. TULLBERG, 'T. 1900. Uber das System der Nagethiere. Nova Acta Reg. Soc. Scient. Upsaliensis. (3), XVIII, Fasc. 2, pp. 329-514. VETTER, B. 1874. Untersuchungen zur vergleichenden Anatomie der Kiemen- und Kiefermuskulatur der Fische. Theil I. Jen. Zeitschr. f. Naturw., VIII, pp. 405-458. 1878. Theil II. Ebenda, XIJ, pp. 481-550. VERSLUYS, JB., J. 1904. Uber Kaumuskeln bei Lacertilia. Anat. Anz., XXIV, pp. 641-644. WATKINSON, GRACE B. 1906. The cranial nerves of Varanus bivitatus. Morph. Jahrb., XXXV, pp. 450-472. Watson, D. M. S. 1911. The skull of Diademodon, with notes,on those of other cynodonts. Ann. Mag. Nat. Hist. (8), VIII, pp. 293-330. 1912. On some reptilian lower jaws. Ann. Mag. Nat. Hist. (8), X, pp. -573-587. 1913. On some features of the structure of the therocephalian skull. Ann. Mag. Nat. Hist. (8), XI, pp. 65-79. 1914. The Deinocephalia, an order of mammal-like reptiles. Proc. Zo0l. Soe. London, pp. 749-786. 1914a. Hunotosaurus africanus Seeley, and the ancestry of the Chelonia. Proc. Zodl. Soc. London, pp. 1011-1020. WIper, H. H. 1909. History of the human body. New York. Pp. 245-248. 166 ANNALS NEW YORK ACADEMY OF SCIENCES ABBREVIATIONS AGQUCEGE DTANCHIANS oi icauus cs's Sas ne reer ne eee ee ne Ad. br. Adductor hyomandrhulariss 29%. eseu sits as sotiw via es ages ~ Ad, Tiys AcOUCEOr MVR UIE oe SS Sie ails 3 os eho ad Whe eS ine e ea Adm, AGGUCLOr iOPERCULEN eas See Se 2 Pees ee eae aie A. 0. Capittemandibularis. 0.2 ocak ee Ree Re CO. ta, Capiti-mandibularis superfi@ialisnd 22 s.c0 concn ds eke » ©, mag: CapitizmanGipularis Meas. joi iki ds Ts awl a cents ee C.m. m. Capiti-mandibularis: protundus 4) .ca 04k Heeeee Peek C.. iy Constrictor) superfiicialis dorsalis ls... uc atk C. ,Sd. Constrictor superiicialis dorsalis (2.0.55 tds oes tile C. .sd. Coraco:Dyoldeus. ci ok: aca GE ee CA ee ees Co. hy. Coracowmandipularise. ncsd fob ek cee ee eee Co. m. DeEpressor sCaDpitSe yore sch ld. bx eal Wea, sel ee Due. Depressor palpebree ImPeriony s Woe, e bes, ob amictars cose Lb. tia Depressonr MONG Mlss, Le. 5 vx Sore aopep athe pieddhns reds ae Dae Depressor mandibule anterior.............e0ece8+ sis dOs nee Detrahens: map do Wie o 56.6.) 6 swe nis cea Bw ak ei es Deine DRASTIC, yess issu. c ele ols, coe ae a ee es ae Dig. Digastricus mandibule: anterior... <<... ais. swrncint4 «see aes Dig. a. Digastricus. mandibuls Posterior e,:. 2% «ites. eee “ieee Dig. p. Dilator OMELEWUI s sew sc 5 scare ae ategse ake Cr eer ran D-o. EE ORE Vy Taare UNC RES «co ade: Sica ails dents Ryan pati nln UREN ee eS Ent. t. Elvomandibiiir= soe Svcs... oe eee Me Ss . Hyo. m. Levator Arcus, palatine 6 2.46 celk. os shee Pion. cic Li asp: HHO VELOT CADIS os. 0 ic ik oneo se bide & al oe es Code ae ee ame : ees hevator abit SUPCTIOTIS. : oe S See eds coe ee eee Th. Lest hevator maxilise superioris.. . i. .ee hes ee ne eee Li, mm, 8: WEVA ODETEDN 6 5.3. f:o. sc a Wise, wees ete, estes ak Lie: MASSCLODOS 22. LOO ge SLES Lene cee ee Mas. Mylo VOLE Cots ees shee dalle’s bee lates Bee My. hy. Parichosnandivulanisss weit... See Sts ee a eee Pa. m. Protractor-hyomandipplaris..< (4 ojosaicnt Se eee P. hy. Ptéerygoigdevs anterior: oes os eR as ee ee Pt. ant. Ptreryeoidens: CREEKS £ KL). olen, «ape 2 eere a anette eee Pt.’ext. Pteny COMMEUS AOTERMUS 22 okie ck)n 32S a kel ame Pt. int. PheryZoOrdews POSTEMIOl: .)5 6 cies acne ae es ee Seo Pt. post. Pteryroideus *parteraliss o.(2ihecc eas i oe cee Pt. pa. Ptery20-Sphenoideaiss Moc tins SSiel, oP elders ic anAlere ee ee Pt. sph. Pterygo-spinosus........ Rea eid Cha Bi aina a aie Getta le eee ee Piss PteryeO-CYIM DAWG Sy in aleCivs << ct sis « 6 ofheva oie lecelss anemee ete eae Pt. ty: Retractor’ Hy oman Mo mlar iss eae aie hele w Sle se a eee ee R. hy. Spiracular Mitiselee aces o tae oes cision @ oe na ee hereon Spir. Sty lowes. <5 cy onsale cate wakes eS eateries Wa ee eee St. Pam POralise ss sek ee ate eae els Suede eaetateys Mimaskotaeein cate baleen Tem. ZY ZOMATICO-W AMA UALS sacs ane rasa noi, Oie Vos sd Sooo he Zy.™m. a ee af ae 7 eee Par aa y ayer se ery pee at Pa La int d ae in x ~ ts + F Pp AR a epee ci eS os = EXPLANATION OF PLATE I Jaw muscles of Scyllium and Acanthias, representing the Elasmobranchii, and of Acipenser and Polyodon, representing the Chondrostei - Fic. 1.—Scyllium (Mustelus). (Muscles mainly after Marion.) The adductor mandibule (Adm.) is seen wrapped arouid the posterior ends of the palatoquadrate and Meckelian cartilages. It is not differentiated into separate parts, although the fibers are crossed in certain regions. The levator maxille superioris(Z. m. s.)and the first dorsal superficial constrictor (C. ,sd.) lie in front of the spiracle and together with the adductor are innervated by the third branch of the fifth cranial nerve (V,;). All the pre-spiracular (pre trematic) jaw muscles of higher vertebrates are derived from this group. Fic. 2.—Acanthias. (Muscles mainly after Marion.) The muscles of the visceral arches may be divided into two sets according as they are derived from muscles which originally ran in a transverse (cir- cular) or in a longitudinal direction (Kingsley). The jaw muscles belong to the circular group, which comprise dorsal and ventral series of constrictors and the adductors of the visceral arches. The levator labii superioris (JZ. l. 8.), levator maxille superioris (Z.m.8.) belong to the series of superficial dorsal constrictors (C. ,sd., C. ,sd., ete.).. The adductor mandibulze (Adm.) belongs to the adductor series. i Fic. 3.—Acipenser. (Muscles partly after Vetter.) The adductor mandibule is small. The levator maxillz superioris is: either absent or not differentiated from the large protractor _ hyomandibularis (P.hy.). This represents C.,sd. of the elasmobranchs. It lies in front of both the spiracle and the hyomandibular and is innervated by V;. The retractor hyomandibularis (Rk. hy.) and the levator operculi (Z.0.) represent C..sd. and are innervated by VII. Fic. 4.—Polyodon. (Muscles partly after Danforth.) The adductor mandibulx is divided into two muscles (Adm', Adm’). The post-spiracular constrictor (innervated by VII) is more or less subdivided into retractor hyomandibularis plus operculi (R. hy. + o-), levator opereuli (ZL. 0.) and adductor operculi (A. 0.). of enoled Waban walled tT: ~. yofagttiA ) - “oebioriib: ae a “t ward ra dina abun a Pea ie” foerst ‘eben ay insides eittane ieee coutliqae ew dionnatonarvontd ort re sie Sip fae: saad 9 tae pbita toraiaoiy ‘ai ‘iniori atctn’ se ai’ Came} aacibittion’S oderi fx alsinereRth jot wt 3° sesathems ilowe Mt bas ote sotavet oY attoigot Ahefrs ust hoadots uy Bedi oat oe ( ya, P16 Pr ieno9 Tetyttenyi feeioh jet dt De (.% oat ya - vd beter ete FORO DBE sit Wiha todteyet bas dba rpriy i qustiasitye- tty ‘bd ee (GV) svisirisinars aftr sift 10° 1 rte ‘vid ; O8T irish ‘hid witiralotna woutgiat tw wooed at eg Strien 2, 1° poe ‘gotten ylaieat, saben). asian ati Aa ee OF OEE “papper ed yntit vodese Laroele off io# ti) 92 {eats ap taal yihenis hte’ ifsihy velvenet «ort “hev erodoiriaie) To “ahrmey esdase bie -ieeteh: setiqmos fotiiw sorry ah (2 Sl atone tilel toievel od > aodots Livocate olt-t0 etddor Ineo eisihrsiue TO" Baliow' uit wt gitoled- (2% aed) ebtebroqire antl ad vanolint et: ane mredineat: 1oto0 DDR ont 999 5 beg: oe The. DE aakioe Mh bb: Saas ee ° = = ~iaaie¥ TottH alieq zolaeisM) ‘rend tic Sb: sdsishinilas xilizout 1oisveatodT ffeaie at oudibupid wotogh ztinin dbase | joe io1g ouint silt, oto peisiiaote nth Vou! diet ‘to pert at niitl 4) 2tboseadomants oil} To 2,0 stages: yo tog eet, eB © ow bedrrotert ef. fice telodibimcpest oft. tne 9 rk payo? paiioaieit (:%nkd) ino% qo Joinvsl adt hae. 4 wl Sis are : Bee. ee ALY, oe iy . | { spot soste afceq doljesth) oft bab’ wibh “eaknamsath on) otal hebivib ab Sy dine YUDDB 9 viai bahivibdae ag 10 Stout Bi ay val boisyromal) ojotanoy, Bly ie ol} iio patavas Ato + el ca ilar riot asthe eitaludibe a ‘ ‘ CO Ky : ' , z . ; ri + 4 ‘ : * a e P $: ; ra, watye . > : is s i is 4 ‘ye i ot eee . = ey a 9) 7 a, r, Pee i ed i » os Mat (a2 Se F Sige, ‘ Agi Aes Ta mh, “ase AF pte Gc, eels ed i ? " Da ve Meee is) CIOS Se a ee ANNALS N. Y. Acap. Sct. VOLUME XXVIII, Puiate I C.3sd Casd C5sd C.gsd Lims.C.4sd C.osd 6s ——— HAAN URN HH NX \\S : KAKO RS . \\\ NY Won Xx NY AX y LAY UX Qn” . AN ~S XA x > RAaQAny QHOSPS SS Adm. Ie: EXPLANATION OF PLATE II Jaw muscles of Amia and Lepidosteus, representing the Ganoidei Holostei, and of Anguilla, representing the Teleostei Apodes Fics. 1 and 2—Amia. (Muscles mainly after Allis.) In the Holostei and Teleostei the adductor mandibule and levator maxille superioris of selachians are subdivided into numerous muscles all lying in front of the hyomandibular and innervated by V;; while the C..sd. group behind the hyomandibular, which is innervated by VII, includes three muscles (Ad. hy., A. o., L. 0.). The levator arcus palatini (LZ. a. p.) and the dilator operculi (D. 0.) belong to the C.,sd. series and appear to represent the pro- tractor hyomandibularis of the sturgeon (Pl. I, Fig. 3). The levator maxillze superioris (L.m. 8s.) includes several slips of which only one is shown. The first division of the adductor mandibule (Adm,) covers the cheek behind the eye and runs from the preoperculum to the mandible. The fourth division (Adm,) is lodged in the Meckelian fossa of the mandible. The dilator operculi (D.0.) passes through a groove or depression in the hyomandibular and is inserted by tendon into the operculum. Fic. 3.—Lepidosteus. In correlation with the anteroposterior elongation of the head the jaw muscles are nearly horizontal instead of. vertical. This oblique insertion gives great speed but low power in the closing of the jaw. The protractor hyomandib- ularis (P. hy.), as in Acipenser (Plate I, Fig. 3), runs from behind the eye to the anterior border of the hyomandibular. The second slip of the adductor is now above the eye instead of behind it. Fies. 4 and 5.—Anguilla sp. In this peculiar teleost the adductor mandibule is greatly enlarged and has spread out upon the top of the skull after the fashion of the capiti-mandib- ularis of certain, Amphibia. The large dilator (D.0.) and levator operculi (LZ. 0.) muscles assist in the strong respiratory movements of the branchial region. ditches somnrel bas shadtbiiat 40%: oubbs oh ibteooia Dass intzolOH ‘ . “O11 ot. durezatot iS qeotdn fais zai she, .") oslt of anolod (0 wi bon ishidibasaovd onl ait sotezeiqeh 410 svootg & ilgrotdt esaasg | bovig soistmeni oupildd eidT, Meottoy to hsotani Lituoxttod ufiont O18 dibuscoyd tojastiotg slT ow si, ot To gnizolo oitt nt Sts, wol ea na er 5 » ) TE araqt ‘to LOVERPMAAZA bas joteolbH lobioaed: ott aihonibiesss snptaoniqa. ‘has wiset h. toa aohogaA inteqolsT adi ‘patliaoaorget Oui te > - (201A “orbs: winipot palsies) fi guiy! Jis eolvavos euotommm obat hobivihdna ote arisiidonioe - to.R quore .pa, ott ofisiw 2.7 yd betevrouni« bee selodibianeto gl oft 4 Bolsa tttit yyy pope h iV vd hoisviount ei teytitw “tnlsdibipato gt» sot nlib adi barn (.4 © wl) intteleq enots teievot stT. Civ ak o A algal 4 iat gilizent totavel of 6 (oft 1 11) moegiunte off Yo aitetidibas mow 10498" oft .avode ei ono “lio doidw to aqila Letevse gobsloal (.2 ae ly ae i101 ‘t edt baited Asoo off sroroo (sah) “olsdibasat sojopbDe ot to eo at ; nolaivib fitisot off aidibusim ot of saonisreqoosg ot mort ast fi ilerrteqo totslib oft .ofdihanat ot To gezot anifodseMt ont at hegbol. At T9qO ot oti obits a ‘ “duotobias wsi, odd bro atl} to soitescois obia jeceaad da on diiw “oitslat109 if i bp a ee a i ioe eoniiiet eae (.0 ‘a ~yosatth onal ott nidtdqenh. aight. fs isidoarid off to ainouroevem Pere atone iit ai iaieas ‘gofoamnt f . eo : Pas ’ = VOLUME XXVIII, PLATE Il EXPLANATION OF PLATE III. , Jaw muscles of Hsoz, representing the Teleostei Haplomi, and of Palinurichthys, representing the Teleostei Acanthopterygii _ Fies. 1 and 2.—Hsox. (Muscles mainly after Vetter.) The superficial muscles are shown in Fig. 1, and the deep muscles in Fig. 2. In this rather primitive teleost the divisions of the adductor are substan- tially the same as in Amia (Pl. II, Figs. 1,2). The protractor hyomandibu- : ‘laris is either absent or not separate from the levator arcus palatini (L. a. p.). _ The fourth branch of the adductor fills the Meckelian fossa of the mandible. The dilator operculi (D. 0.) passes above the hyomandibular and the pre- - operculum in the normal manner. ‘ 4 Fies. 3-5.-—Palinurichthys. (Identification of muscles after Vetter in Perca.) _ These are the jaw muscles of a highly evoived teleost. The protractor : hyomandibularis (P.hy.) is distinct from the well developed levator arcus -palatini (L.a.p.). The retractor hyomandibularis (R. hy.), the levator oper- — euli (L. 0.) and the so-called trapezius of the pectoral girdle are extended for- a ward above the orbit, on either side Sg the sagittal crest. ee a A) isiteaind eitoik tony: of oft mort siatsqex tem 10 tnoads 15H ih + bed $ 5 ‘ ¢ : 4 =" ¥ ‘ oe F rey, fas a sa . * Met! : oa* Ley : Bae > y % a es > 7 i“ ae Sp yee ~ he re 5 a, . fA 5. >. t 5 Se et i a ~ ee ‘ Pp af we et sae . s ‘ x ; ‘ te, r ' r ue k, f i: A . : > oT es i $ ae 2 ies Sa “ees roe — rp a Ae 5 id . ~ ? 5 a 1 - > . f= Lis ’ f eeu.” =) b 5 ee te he J ~ a ~~ ¥ . Ys / \y, 5 7 \ ; ¥ 7 " : ‘ = 2 ‘ : i] —_ e ‘s re p . HTL gr209 a6 vorraviaraxl 40 bas ,limolgeH iotzosloT 919 paiiadseoiqet 08h 10 ‘asloatsst ligvioiqoisaand | letaobloT wilt aattieneneT RATE On\Y van gilt __. (197 tyis cute alone ¥ mow J bt © «wid al zoberns qoob odt bus ¢ 2a wwode 916 e9lornm tatoiealy «I stgiedne oie - totubha odt to anoleivify of? te00f) eviitming ‘tot eE udibanmoyvd totestow oT £1 oath 10 ID) winch at 2e Ber ‘oldibasar oft to g2e0t ieilodos od) allt Yotouhibs oft to° fonntd of ei oft Dos teiedibasooyd gilt rod st Cor (0 AX) ilsoredgo ; eH ESN i erereoet ont ak bye ni totieT totte eoloeuen Yo doitscitiiaebly . aii vevieneihi, : iwioetiowg eiT .Ja0sist- be'vlove yiilgid. & To zolozinon wit eilt alts DEY LE yoleval haqolorah ‘Pow. od otort dootteib 4f (.gh A) 2iuslssdl “tago TOIBTSL 9d .¢.yh A) al rafudibasinovl 1OIIBIIYI oft cae ot bohbuetzs ots affifg Letotssq oi To aoixoqeu beliss-oe otk Diss (0 : teem (ntiizes 401 to obia. toi ao Jide »-oift ato ty ne _¢ . ~ - . ~ > ¥ s , - a i . = os “ e \ . - ¥ « ‘ >» id - oe a p- ‘ la i aS ~ * a Sat eu Sid ANNALS N. Y. ACAD. Sct. VOLUME XXVIII, Puate III EXPLANATION OF PLATE IV Jaw muscles of Polypterus, representing the Crossopterygii, and of Neoceratodus, representing the Dipnoi 4 Fies. 1 and 2.+-Polypterus. (Muscles mainly after Pollard.) The deep muscles are shown in Fig. 1, after the removal of the preoper- culum, and the superficial muscles in Fig. 2. The superficial layer of the adductor mandibule (Adm.') extends from the enlarged hyomandibular to the ascending ramus of the mandible. The deep ; branches (Adm.’, Adm.*) run nearly at right angles to the outer branch and arise from the side of the skull. This arrangement foreshadows the differen- tiation of the jaw muscles in amphibians into masseter, temporal and ptery- goid branches (Pollard). The levator maxille superioris (LZ. m.s.) is closely associated with the protractor hyomandibularis (P. hy.) as in elasmobranchs. A small slip of the latter muscle runs dorsad to the spiracular ossicle. The dilator operculi (D.0.) seems to be absent. In Fig. 1 the hyomandibular is seen with the area of origin of the adductor mandibule on its anterior border. hen The levator opereuli (Z.0.) is closely associated with the adductor hyoman- dibularis (Ad. hy.). Fie. 3.—Neoceratodus. Side view of jaw muscles. The superficial layer of the adductor is fastened posteriorly to the opercular region. The middle layer (Adm.’) runs over the top of the massive chon- drocranium and separates the dermal skull roof from it. This part of the adductor is divided into numerous small fascicles interspersed with connective tissue. Vic. 4.—Neoceratodus. Viewed from above. 5 ae ‘ aS + a Ba € f me, ee eh | ~ ‘ ao se Z i | ‘ . was Mao” hinds eek - ’ 7 rs AF J Sie Sage Al mot . > . ao , 4 Mis 4 ty t Part . LAAN 4x, (RS " a A aK — 4 - te - eau < a Pe, am \S he oth Yead te 3 ; ea Yo oe A " ‘, ri lie A. ! ah eee iene os : ina oa, . 4 S ; °4 —< 3 ¢ - i ea i \ = Eis Abe Se? « f ¢ ~ % oa ee 5 \ eo 5 : a a Ee ee ~ eet | a a i: Rie dee ie * Z | as ' ‘ a3 Reerie's , | sotpen . a L beats tS Th ; Vi aTaid 40 ROTC EEN ae to bud .iigyietqorso1D alt ‘paitas291q91 - ‘Gaia io rot wih Bh ee res onli gabinaestqor BwHOLN1IV0S V ane aoe Es bm. Wi F " M ‘ * ie Z 4k 2 ; fs Sa NL % cal? a | basitol Torte Gates zatoesM). Awe A GQylod—S- ~ ggqoatg oft to Levoast 4} sotta .t git nt mvode ois eolsauat aot e evn ae ; © ofl of eoloanat Leivitieque ont ‘eo ae LS i, te, ot mort ebito3z9 @. stl b) skiniibecibar To} DhG ost To t9y,6b Igioftte Tr ; “ee qoob ofT = oldibasest off to anniet 2oibisoee ait of ieiodihaageneaay cay Ze bas doacid “soino of} oF eofgas tileit 36 Wine ct (*.seb AK * seh) 4 PEE ths =o -no1shib od} evobndeotol Jnomeganis ail'T Atirae, ott ‘to obia oat} am at : og yretg bas | RIOgMms! istozenot obat ececididqars iti aol oHiF ce WSL, oil To ne a ae ylozolo at (.8 at...) aitoiteqne silica sotsvol ofl . (bteifoL) @ foot é ~- sfoieidoaezelo ai es (ul ..) siteludibasmoyd totsetioig off ditw of £ ee as. |: GAR > afobaso “—slysetige 91) of beetob ext oloana 191 sl gilt to a Pit eh isindibusmoyd ot © 2th al taseds -od ot 2arg92 (.0 A) ‘ils Sees, “ebiod toftetas gti a6 stidibasea totoubbs of} to migtso to OTE WEE oh is ‘ramoyidl totomhbs ot tibw hots O22 L yfozols Bi (av) Htnorsaq-4 ) Re igs ; : kes Sean yh) 4 4 4 s = ‘Retain wai, to wetv obiz subotw noah +24 gle isibotsgo ot of Utoltsizog beastest ai tojonbbs oft to 196! sini re 2 Ge ee “toily ovieanim oft Ye got od t9vo aout (f.sb.) noe ol bbin Grae Sh Ce ae iieg Bid? 3 mort toot Linda Isartoh arth, Bg IB IAYIA burs “ \ atiteenios ditw heersqeiotit 2oloivast eare enoromrt otal babivib A riots mott bowel .anholive ee ; ae 5: mA AnS N. ¥. ACAD. SCI. VOLUME XXVIII, PLatE IV IEXXPLANATION OF PLATE V Jaw muscles of Rana, representing the Anura, and of Cryptobranchus japon- icus, Amphiuma and Amblystoma, representing the Urodela * Jn all modern Amphibia, owing to the loss of most of the derm bones coyver- ing the occiput and temporal region, the jaw muscles lie immediately beneath the skin and extend above the parietals. The muscles are divided into a pre- trematic group, in front of the squamosal and quadrate, innervated by V;, and a posttrematic group behind the squamosal and quadrate, innervated by VII. at Figs. 1 and 2.—-Rana. (Muscles after Ecker and Wiedersheim. ) 4 ots. “The superficial muscles after the removal of the maxilla are shown in Fig. 1, and the deep muscles in Fig. 2. : The adductor mass of fishes is now represented by the capiti-mandibularis (C.m.), which is divided into anterior and posterior slips running respectively from the squamosal and quadrate to the mandible. The deep part runs from the under side of the squamosal to the mandible. The pterygoideus anterior (Pt. ant.) probably represents the deepest part of the adductor mass. The depressor mandibule (D.m.) lies entirely behind the otic region and is inner- vated by the 7th nerve; it may have been derived from the retractor hyoman- dibularis of fish (Pollard). ‘Fig. 3.—Cryptobranchus japonicus. (Muscles mainly after Humphrey.) The deep anterior part of the adductor mass of fish is here represented by t the much-enlarged pterygoideus anterior, the outer part by the capiti-man- _ dibularis superficialis (C.m.s.), while the levator maxille superioris may be _ represented by the capiti-mandibularis profundus (C.m.p.) and pterygoideus posterior. The depressor mandibule is divided into two parts, of which the wef anterior is large. _ Fic. 4—The same seen from above. Fie. 5.—Amphiuma. (Muscles mainly after Driiner. ) Fires. 6 and 7.—Amblystoma. (Muscles mainly after Driiner.) The superficial and middle layers of the jaw muscles are seen in Fig. 6, and _ the deep muscles after the reflection of the capiti-mandibularis in Fig. 7. ‘ - HA ae y y ’ est a BT ae i, p - se re “ Og ae r < { 5 : es ne as ie ce se ait 32 EN oo eS Pee & ; hee 5 a << es, iid. Ye ag PP Re GaAs an Co eo ee = r i a ee * Ps ? pe mae 2 ) ir at ? i ee Yam - i Fo5. ‘ ~ : i ‘e Brat Fes 3 ; ; OM \ } : 2 . 7 r ee a S Vo arard YW vorravasitzel i = ” ee » ? ‘ eal a woe an dsenidoyqy ed to bus simak ot eaitasesiget uni To 2aioe! slohorty off goiteseotqet .weotagldiwh Dios sess Naqant BL sole Hinoapd ilotsiboumai ‘ott ininayle WAL eds paege favoqunad Dias isatoon. ie “vy & oisi bobivih ots eolvenon od’T fate Be oii svods basize’ Dae i . bus ..V vd botevtonai Sisibayp bis [pzoursupe off to daost ai «ors | va si JIV « Doin Trem. stetbsep bas tneomogipe alt hekdod agora oe sor Ee f sitioderoboi Die toast otis eoloanl). - eiacs s bas i yacy2: re Baris ‘pallie qobmteog bis toons “plat bobivib et foity mom aust jeg geob oT oldibunit ot ot sisibenp bas incomes 9 qortsian zpobiog viol oT S{dibusar ot of taeomiaupe ox? ‘to obi. sf{T .w2aesat totoubbs ont to Jinq izoqosh oft aiudeo1qot udadoig - -yonai 2i bur moreet sito odt fisted ‘“ietiine 2oif «sw ) olsdibagen 4 0% _ -ftrono wil TOIOBTIST od? mot heviteb aie yred- vent Jt; orton iy oft : ey . _(saffoT) det to. « AG stiqeanh, setts eSicblint ant aS) BNDIMOGDE sintonvwWodqyreds “ad botaseo1qot oto ai dell to eanut sotonbbe ot to eq torodaK ood | iT -inm-iiqss sft yd sq 19i0 9dt iorteinr apobiogyisilg boy isias-domet of yeu siteieque Gllizsar toigvel oft olidvr ,(.% 0 AY) ailsioiiequa & isiud atebionvioig bus (4 ae) aubastoig aitsiudibasariiqns oft yd hot ot il vjidvwy to 2ttaq owt oti bebivib ai osirdiber sar ToR29 Tab fT - e ee at rods atott 199% 96K ot (19nd 19tle waisor 2olenW) “pw dqaeh— (19nd tofte waite zofoentl) awodanphvsat kh, 7 bas bor 2 .2iff ai 1998 916 eoloeiiint whi, oli to etoyel sibbint bas istoitase J 2ff ai eitsisdibarne ee ant te aotmotter odi tote Zoloenstt ' VOLUME XXVIII, Puate V “i, a ' ar] a : Ww / . ; shed ( prong et »olenrin qood asstonigtrodttin Pn ge yok. * POLE Biota 8-05 beosiis zi (.awoT) ail mioq«tas oft to bus 1oboiit os. Ott To aas90%qg Diewetos oft 09 mt ait to fofgot [stidvoteaodg oft woit x * aiiobiog yet ot swolorabus of Yo doustd vitemorys off dtsonodl al dit % ; a) ; os? | . ies 11992 ab (489 AL) oir ys ws re y oe wy a me LS ; . nau CORO ie oe Pol ven ae veel ont to aiusatily sits oil) guivoile soled mrost aso2 old bar ’ mo hy y sy : Ba na a : , - 9 71Odk wort 11992 Of ot br a7 a ame Peek RA ‘7 dedai i 4 19vtp Tidisat aeloaslt) ce hee Bt : ‘ oy ae of Pane ” gywpet ait To nel tai bon tory fute soitibinos enolrtinebe ot Miia oi BloT1O? f oe ate eldoot todtet 918 colozim (20M) jorodenm bug ¢. seo'D) sltowoqatad “herO at a8 enna ott Hishnominiayst «i 197ovon ..ofanot od}. to reMtes is wdadet 4: zindionct to ofdessih oft to xHod, tolteteog odT ae 6 poy ie AVY vdsbotwrroani (4%) 20 obiordobyte oft to req sorrotis ont yd boine nee, aludifus zaodeioh odt qd balasriqot ldbdorg at, (Hod TORO ai 9 sh var bio cdot rus ot of boteisy et Dries Ved Botertomat ai oisty .(-D dt WY 4a cc eae . f ps ij ae Rs ° _ ne er; 4 - : tobe. a ‘ r 4 ¥ — ‘ tails = ANNALS N. Y. AcapD. Sci. VOLUME XXVIII, Puate IX Tem. * _ \ EXPLANATION OF PLATE X Jaw muscles of typical mammals: Didelphys, Solenodon, Mus, and Homo In mammals the jaw muscles in front of the auditory meatus are derived from the capiti-mandibularis of reptiles and are innervated by the nerve V;. The depressor mandibule of the reptiles has disappeared and is functionally re- placed by the digastric which is originally a compound muscle characteristic of marsupials and placentals. The posterior belly of the digastric (Dig. p.) probably represents a separate slip of the stylohyoideus, both muscles being innervated by closely associated branches of the seventh nerve. The anterior belly (Dig.a.) belongs with the ventral throat muscles and is innervated by the mylohyoid branch of V.. Fic. 1.—Didelphys. Superficial muscles. In correlation with the carnivorous habits and orthal jaw motion the tem. poralis and masseter are both powerfully developed, while the external ptery- goid (Fig. 2) is relatively small. The anterior and posterior bellies of the digastric (Dig. a., Dig. p.) are in the normal mammalian position. Fic. 3.—Solenodon. Superficial muscles. The masseter is considerably enlarged and its principal attachment is not on the slender zygomatic arch, but on the masseteric tubercle of the maxillary beneath the orbit. This is often the case in animals with piercing front teeth. The jaw muscles as a whole are of the carnivorous type. _ Fic. 4,—Solenodon. Deep muscles, showing the weak external pterygoid (Pt. ezt.). Fic. 5—Mus. Superficial muscles. The masseter is extended forward beneath the zygomatic arch in front of the orbit, crossing the temporalis nearly at a right angle. Fic. 6-—Mus. Deep muscles. Fic. 7.—Homo. Superficial muscles. I'1c. 8.—Homo. Deep muscles. ’ 2 Y avast w vorravaiacd ¥ Ge ‘niG) SEE ot to vied sobtateoq ont ainia Rant ponte oink ae ; giifed zoloenin dod »vobioydolyie edt to qile 91 B1KG92.—6 mesa \ ¥ SeO WOM oka * — use Dis wih ‘trohonaleg, BY AQVODI : siuritaat ites ted to sofas 7 Dy f ws <2 beviteb sin auinedu Ciotibus aft to ecrtt 1 i pel: yeni wet ot. “Asaimnan oT aV¥ @ eT ot 7d hateviuat 916 B bas Pend » atralieGth cae: fi te 107 (9306 off orton dtavvee ot to aodernrid botsisoazs tlasoly yd vil holsvTouni vi has eofoanma ipods eine oli diiv aguofed {4 nic \ ‘\ oF to ds gud er ‘ 2stemi Lsioitioqu4 uli rot ott doivort west ledii Dos atidgd auto TINT) ot cite Hott nov yal -yratq [murtatz9 ott oltebe .boqolatab “introwod iliod 916 1otez2Rar. bas ai rt oiit to aolliod 4obi9I40g buss voirotis ofT ~ Aiparte pqiortision at. (& it), ob izoeg usilporat Bon PRcrToM oult af ove (.q QV Lp wid) ¢ he vweabani Ininitroqua nance mo jot af ae »etTE isqi: mig ati bas hegisiae widerobiaio9 at rolovenett 8 qitibesoar ot to slotsdyt oitotsaznat off) fo tod dose oft eatogys tobarok ifieot juowt wuiowig Mive bleattss ni 9209 oft motto et eid lidto oars Ceo a) biow’ cisiq igittotze Asow oft aitivvorle olen jo Junot? at dow Sitsmo2zys oft aod bis wiot ines “i “olsranar on Tait it ight hie wirseu eilsteqarad ott 3 BiNeeOaT, on * : ol vane Ltt ool “Ma, a ee i iets { ‘ : vobanor [sivitiegu4 oo? veloann good one : ; / ty? E BE ye baa ~ i wer Py oa, VoLuME XXVIII, Puate X s; -_, os j , \ A s » i. LY Sema Te: : ne we vx ‘ Sa 7 ~~ nT) YACLABAE : M "s Ry PS. ‘ “ : ioe ok ie Dy a ; Doe ey) ee = % y by es : . ‘ Lae ! ‘ t \ penta ' =" a 5 = P —_ 2 J . at : yo 4 j ; 1 \ “ : , A ; “oy / i Ff ; J : EXPLANATION OF Pirate XI ° } : > : - . 4 — ~ Fe ion of the jaw muscles of Dinichthys, representing the - ay , Arthrodira 2 ae closed, depressor reapitis (D.c.) contracted, levator capitis (L.c.) ex- \ % i } 4 « ‘ és . é : / y ‘ a" = " , 7 . Pia ’ ie i‘ 4 » . 3* + — ; | m - — e- 4 “ee > < : if » 4 7 *,°* . i . a iS o@ " “ns a eae - - = ve fr / 7 4 rat Ta ; ‘ ay hn iy 1X ward so vorrevass24 - 9d¢ pattoseorgot aldo to zafsenra ws, ai to A stibordink | = r ¥ a9 (5A) aitiqns todg7ol botostitoes (9 a) afte somos hoe! + ANNALS N. Y. AcAD. SCI. VOLUME XXVIII, Plate XI EXPLANATION OF PLATE XII Restoration of the jaw muscles of Eryops, representing the Temnospondyli, and of Labidosaurus, ers the Cotylosauria Fic. 5 Be yops. Superficial muscles. _ Very probably the jaw muscles of this form were fundamentally similar to those of modern amphibians and include superficial, middle and deep layers of _ the capiti-mandibularis (C.m.). The pterygoideus anterior (Pt. ant.) very _ probably had the normal course and crossed the capiti-mandibularis on the — inner side. The jaw was doubtless depressed by the depressor mandibule —(D. m.) lying behind the itis A a 7 icc 2-4. _Labidosaurus. ____ As in the Temnospondyli (Fig. 1) the jaw muscles were entirely beneath the ermal skull roof. The capiti-mandibularis was probably differentiated into three layers and was inserted into the Meckelian fossa of the mandible, and the pterygoideus anterior probably crossed beneath these, being inserted on the ack of the mandible. = ~ 4 ang.— angular d. =dentary art. = articular ; pa. = prearticular cor. = coronoid i sp. = splenial Waal — > ee eT ae Ae Soy “) at eal _ ng’ ./ ; &. dae ig, eo PAS crane seo + ; a bk ba Sits rs LN nis 7 BYP irpa, 3 ~ es ‘ Ewe r ob 2 ue Goes : ioe? . Aas GF ns ; Se St - iS wis heel 7 Lia! - ; a mi! : s i Pe Aa Fak. Bsr “alee 5 + Ane! M rs me =e eee ots Sie ge at Ae a e 4 = ~ : _— : ¥ BR ~ ier 7 i al. eS = s + i Lie i @ ~ z ~ rn y % , ™ Fy | cpigdi ba tat Toxnotyo oils 4 Beesotqoh eeoltdioh asn wel ofT wobia : f 1iZ% araak so vorravarizcl ~~ 5 ed : Mets Mel inte Jf ‘buroqeousag ails wart uonetyot ago to aeloauin wei, ot ‘to othe sf Br keol eo! } oft guitusezo1get ewineohid ond te 2 \ = : olc-untiwie vistwooshunl wow viet “int To neiodirant: wat ott ideueadh to ays qaeh bus olbbion jsiottiogs. sbutoai Dk anetdinqars itebout | vier (Aen SA) solrotas zoobionyieig off .(. me SD) 4 aiisisdibasa-ii oft 16 aitslidibiner-Digss oft beaset han sto» Tnarion df baat 4 ia | _ sistbeap oft baited om 1 * on boteidierottih Fiasestiace BIW abr nleniieeedan! Diqe ‘ol “tor ile hit oldibirne oft to next ugilotoolt ot ota botiseni aa Dens 219) sft 10 betigeut gated D208 T, iltsecdeod hoax) yidadorg Oro nh aiabion TI oidibason ot 90 4 wisineh == Db “telugais = wih tnlooiitieeitg =< .G¢q ; P ipiooitin == a1 en, fsineiquz == «7a " flonto109 = 109 Beet - y : . : m “ Fs ra ia) AN ad a ~~ "Annats N. Y. Acap. Sct. VOLUME XXVIII, Prater XII tT 1 LILIIT? eae eo! tae oie ae tnt Bd ete ah oe $e oo EXPLANATION OF PLATE XIII Restoration of the jaw muscles of Tyrannosaurus, representing the Dinosauria Theropoda, and of Cynognathus, representing the Therapsida ; Fie. 1.— Tyrannosaurus. Superficial muscles. _ As in many other reptiles, the capiti-mandibularis (C.m.s.) was probably a ferentiated into three layers, the more superficial layer of which (C.m.) is analogous with the masseter of higher types of mammals. The supratemporal | fenestra was probably filled by the middle and deep layers. The pterygoideus = anterior may have filled the space beneath the preorbital fenestra. ag Bies. 2-5.—Cynognathus. Jaw muscles. ang A distant approach to mammalian conditions is seen in the reduction of the ; _ posterior jaw elements and in the enlargement of the ascending ramus of the _ dentary. Very probably the outer layer of the capiti-mandibularis was attached 7 to the lower border of the zygomatic arch in the position of its homologue, the Ammalian masseter. The middle and deep layers fill the temporal fossa as in mammals. Cynognathus probably still retained the reptilian pterygoideus : anterior which does not appear to be homologous with either of the pterygoid uscles of mammals, but may possibly be represented by the tensor tympani. ‘The capiti-mandibularis was in a better position to give rise to these muscles. “a true depressor mandibule (D.m.) was doubtless present and the general ar- ra ‘angement of the muscles was reptilian in type. A.) = articular (inside) re D. == dentary Ang. = angular P. art. = prearticular Art. =articular (outside) Sur. a.= surangular Cr. =coronoid é cuts ea » , a we . » i ae yar it. arth A a ae + oe ee 5 Fk 4 he PP oe ee 2 oe ar =e! > Pt oe s Teas APRS. Rete Fan eit OES, Bete tae re fe odbe a oe sgh , < : Me ~ Fis ‘45 ald aid a q nage? p stieeonicl ott unitiezetyet masiinsonioeay L to zatoanun wet ott to dot | qidgdoig eew (aww) aitslodibasa-Biqss of .zoliiqet 49dt0- but a ef (40.9) doidw to to et Isivitioque stom oft 2roysl gotdt otat beis THX avezad wo eovrawaaizl x shieqaiodT ost} Baissea igor” BM Rann a) ‘to has sboqotadt Be es r velsannun Laisiveque BMA DBO TD — irrogestaique dT zines to eo(pyt todgint: to oto2ea.RO1 oils fiw. ayebiorviotg ofE 1978! qoob bas sibbint lt yd hollit widsdosq, 2BW # ftieaiicl Istidiosig off dinsned spq4 1h} boli ovsd TOKE € Prat e pre ee qet, aw iinsnony— git to doitsnbes oft ati 199% vt eooitibaes asifsoraisor oF dosongas-4d edt to auinet 2aibueozs off to taomogtaiae oft at Poitss Ausimols whi hofoniis as efraludihake: st at 10 19" tal 19Tno ot “dedotg. TIOY, 2h aaeet fstoqared ould [ ia tated qo9b bas office. “oT s9t92aeur a8 eyoblowgieig asiiiiyot oft benisiet lite yidsdorg awit boson ” Ranisiieiie bioy 199g ot to tontio iw euozolomod od o} te9qqK8 tom 220b doit to . Joaqmays toasst oft yd botasezo1qor od tidiazog ~waur tad, AI GUTH GO jo e ve ealoeumt 9296t of o2it 9vig of soitieog “9tied 5 il 2a% zitaisdibascie-t -~8 fgrodon ot his tioworg zeoltdgeb area (0.0) mindibasar 10229T6 py) at asiliiqet enw eeloemar oft to 409 Visinoeb = mo J (atiieads 4 ginoitis = ALi Hoty tes Se OE Sloe = salremeine ==. UTA (gbizivo) teluoitts == ‘ hioutotons y ; fig -. oe. _ AnNats N. Y. Acap. Sct. VoLuME XXVIII, Pare XIII Pt.ant. = ind c+ Se? “er, ad mz +». rc pi ra > 4 i... a 4 ae me eee Re atop fe EY ge | - i eee > Tadiin — | f P = meer os) - a2 a. - o ~ - 7 - ‘ * + . a t , s ; ANNALS OF THE NEW YORK ACADEMY OF SCIENCES far s¥) che | >a Vol. XXVIII, pp. 167-200 Editor, RatpH W. Tower lied yy £ a y 2 pre A ONTRIBUTIONS TO THE HERPETOLOGY | OF PORTO RICO BY Kart PATTERSON SCHMIDT ao, ~~ weonian insite ~ “< oun =D t: tute, ~ FEB 19 1921 \ Vy, e/ ; P oO 4 “Ciona) muse NEW YORK PUBLISHED BY THE ACADEMY 8 SEPTEMBER, 1920 3 na + ifs " Pav ; “eae ; hs? Ieee Ft me a = ara ae ee. Sh! Saba i A * P } THE NEW YORK ACADEMY OF SCIENCES — | (Lyceum or Natura History, 1817-1876) i ‘ae OFFICERS, 1920 es President—Epwarp L. THORNDIKE Vice-Presidents—WI1LLIAM J. GIES, CHARLES L. BristTou, IsalaH BowMAN, Ropert S. WoopwortH na Corresponding Secretary—Hunry E. CrRaAMpTron Recording Secretary—Ratpn W. Tower Treasurer—JOHN 'TATLOCK Librarian—Raten W. Tower - _Bditor—Ratex W. Tower SECTION OF ASTRONOMY, PHYSICS AND CHEMIST Chairman—WritiAM J. Gres Secretary—Wautrr H. Eppy SECTION OF BIOLOGY — Chairman—CHARLES L. BRISTOL Secretary—Rosert C. Murrny SECTION OF GEOLOGY AND MINERALOGY Charman—IsaAIAH BOWMAN Secretary—CHARLES C. Mook SHCTION OF ANTHROPOLOGY AND PSYCHOLOGY er my Chairman—Rosert S. WoopwortH ee - Secretary—Rosert H. Lowi The sessions of the Academy are held on Monday evenings at 0 ‘clock from October to May, inclusive, at The American Museu [Au wats N. Y. Acap. Scr., Vol. XXVIII, pp. 167-200. 8S September, 1920] _ CONTRIBUTIONS TO THE HERPETOLOGY OF PORTO RICO me, a By Kart PATTERSON SCHMIDT ia 5 ' niga ‘As a part of the Scientific Survey of Porto Rico inaugurated by the New York Academy of Sciences and carried on with the codperation of American Museum of Natural History and,other institutions, it was 4 wy good fortune to conduct the first herpetological field-work in the ie ummer of 1919. For this purpose Mrs. Schmidt and I spent the period & from August 3 to October 8 on Porto Rico and the aiaie islands, h are under the same political jurisdiction. For cordial assistance in furthering our work, I am Geet grateful . r. and Mrs. B. A. Wall, of San Juan; Mr. E. M. Bruner, Forester of (0 Rico; Mr. Mare Lejeune, of Ricco, who made possible the trip Po ona Island, and to Colonel George A. Shanton, Chief of the Insular nd lice. a 1e Saad yee and exhaustive “Herpetology of Porto = ald and bia fiche the study of habits and habitat vamos id B15 190 24 Dr. . Stejneger has given an excellent résumé of herpetological work on Porto Rico previous to his own. The herpetological papers which haveers: seuss Ap Besred since 1902 relating to the fauna under consideration are given nthe bibliography at the close of this paper. | os Collections were made on the islands of Porto Rico, Mona, Vieques and . Julebra. Notes on the relation between the distribution of the species the types of habitat will be found below under the discussion of vidual species. The addition of six species of EHleutherodactylus to Porto Rican fauna, five of which are here described as new, is an ee cpected result of the expedition. All but one of these were captured | ith the aid of an electric hand-lamp while they were singing at night. Ch ris method of stalking is well known to those who have studied the tes of amphibians. The voices of EHleutherodactylus, as of other frogs nd toads, are useful characters for distinguishing the species. The expedition secured over twelve hundred specimens, comprising ty-one species. ‘To this collection are added more than a hundred pecimens obtained by previous expeditions of the survey (H. E. Anthony, i. Jones, F. E. Lutz, R. W. Miner, J. T. Nichols), making the total i (167) 168 ANNALS NEW YORK ACADEMY OF SCIENCES number of specimens, on which this report is based, much larger than any previously made in Porto Rico and equaling in completeness that of the National Museum. : The present paper is preliminary to the general account of the herpe- tology of Porto Rico to be published by the New York Academy of Sciences in the volumes embodying the results of the Scientific Survey of Porto Rico and the Virgin Islands. AMPHIBIA Bufo Laurenti Bufo lemur (Cope) This species, five specimens of which were collected at Coamo Springs, has previously been known from the north side of Porto Rico; the only exact locality being given as Arecibo by Stejneger. Its occurrence at Coamo Springs, nearly at the opposite side of the island, proves that it is widely distributed. The five half-grown specimens are so nearly uniform and were found in so circumscribed an area that they probably are members of a single brood. They agree in coloration with the juvenile specimen described by Stejneger (1904, p. 572) and all show the hour-glass shaped dark mark on the shoulders. The dimensions of one of these specimens may be compared with those of an adult recorded by Stejneger: A. M. N. H. U.S. N. M. No. 10151 No. 27148 Tip of snout LOMvent ...2c 6'< sar ivi oie oe ee oan ee a 37 mm. 83 mm. Tip of snout to posterior edge of tympanum......... AD es GLO es Greatest wadth of heads. . ost. . + Heoakic wee eee eee 1. ee 5 ea Moretes from, Zexatle 555 oie Sa elon castes ore crere ee eee eaves Dili r oh Ee. Him lee fromayent 5.31 se & oie a cutee tio ome eiole ee ae Olas Sy Geeks 99. 5% ‘The stomach contents of these specimens included ant remains, beetle — wings, an insect larva, and segments of a small millipede. Leptodactylus Fitzinger Leptodactylus albilabris (Giinther) The following localities are represented by sixty-three specimens in the collections: Adjuntas, Aibonito, Bayamon, Caguas, Coamo Springs, Maricao, San Turce, Utuado, E] Yunque, and Culebra Island. This species exhibits a great variability in coloration, with a relative uniformity in structural characters. Fowler (1918, p. 3, Fig. 1) has — figured the extremes of color pattern in Porto Rican specimens. Of fifty specimens in the present series, seven have the broad median stripe on the back, the others varying chiefly in the distinctness of the dorsal V- shaped markings. The measurements of the largest specimen and of one apparently recently transformed are as follows: No. 10182 Re. 10036 EMIEDIEL SCO VOT ooo ci sc ine se nivk soe abet es an ankle eS 49 mm." 16 mm. ‘Tip of snout to posterior edge of tympanum.......... os a (5 ieee ne MOTH OL NEADS oin3 iiss FS wie Sieie als ed ee x OY Saag 7 aa ; EREDAR PTT EA CGS a3. 5k jain com 8S chelate ow Wd mold a oo Se y | 10 7 Hind leg from vent to tip of longest toe.............. Pe 24 - Eight of twenty-five stomachs examined were empty. Four contained pend snails; two contained spiders (one a large lycosid spider and egg sack) ; two contained ants; two contained beetles; two contained bugs; | two contained flies (Muscidz) ; one a small moth; one a large caterpillar ; one a medium-sized cockroach; and seven the remains of an unidenti- _ fiable insect. The nest of this species was observed by Stejneger (1904, p. 579) : under a flat stone in a stream. Peters (1877, Monatsber. Akad. Wiss. Berlin, 1876, p. 709) records one observed by Gundlach in a “wet bur-, row.’ At Coamo Springs, on the terrace behind the bath-houses of the hotel, the water of some of the springs forms a permanent rivulet at the base of the cliff. Leptodactylus albilabris was abundant on the terrace, beneath loose stones. Under a large stone at the edge of the creek, on _ August 27, 1919, I found a shallow, rounded excavation, 6 or 7 cm. in diameter and about 3 cm. deep, filled with a mass of white foam, in which were the small tadpoles of this species (12 mm. in length, body 3-4 mm.). There were between seventy-five and one hundred tadpoles in the foam-mass, and not confined to the central hollow, as described by Stejneger. The bottom of the excavation was about 3 cm. above the water level. Two similar excavations, though empty, were discovered in the immediate vicinity, in the same relative position with reference to the water. On August 29, near Bayamon, a small mass of foam, between 3 and 4 cm. in diameter, containing similar tadpoles, was found under a stone on a hilltop, with no water whatever in the neighborhood. On October 1, near the Forester’s cabin, on El Yunque, at about 1200 feet, a nest of this species was observed under a rotten log, beside a pool of standing water (also at a slightly higher level than that of the water). This nest contained between 150 and 200 eggs uniformly distributed _ 1144 mm., given by Stejneger (1904, pp. 576, 578), is obviously a misprint. SCHMIDT, THE HERPETOLOGY OF PORTO RICO 169. 170 ‘ANNALS NEW YORK ACADEMY OF SCIENCES through the foam and with no central hollow. It was somewhat larger than those previously observed, measuring 8 cm. in diameter. The eggs — are light yellow, and measure 2.5 mm. to 3 mm. in diameter. The small- est tadpoles taken, swimming at large, measure 6 mm. in body length, which probably represents their maximum size at the time they escape from the foam. It is evident that the tadpoles usually will be washed from the nest into the adjacent water by a flood or heavy rain. The — small nest isolated from water was probably a mistake on the part of the frog, and the nest described by Stejneger under water probably had been covered by a rise in the creek after the deposition of the eggs. The largest larve, nearly ready to transform, measure 13 mm. from snout to — vent. The V-shaped dorsal markings are already evident in the tadpoles at this stage. The median dorsal white line is probably an adult char- acter. } Eleutherodactylus Duméril and Bibron Eleutherodactylus auriculatus (Cope) The following localities are represented by two hundred and seven specimens in the collection: Adjuntas, Aibonito, Alto Manzano, Catafio, Coamo Springs, Jayuya, Maricao, Rio Piedras, San Turce, Vega Baja, and El Yunque. Hleutherodactylus auriculatus occurs in Santo Domingo — and Cuba as well as in Porto Rico, the type locality being Cuba. It ap- pears to be rare in Cuba and Santo Domingo, while in Porto Rico it is exceeded in abundance only by the ubiquitous Leptodactylus albilabris. — Its closest relative appears to be the H. martinicensis of the Lesser An-~ tilles. . E. auriculatus is remarkable for its color variation, with a compara- tively stable structure, but a considerable variation in measurements. A specimen in the collection of Prof. G. E. Johnson, of the University of Porto Rico, collected by him in the Luquillo Forest, is remarkable for its size, but it apparently is a giant individual of #. awriculatus. The maxi- mum size in over three hundred specimens in the National Museum and the present collection is 44 mm. from snout to vent, while Professor Johnson’s specimen measures 52 mm. Its measurements compared with the largest in the present series are as follows: A. MLN. H. No. 10241 Johnson coll. TipOF SHOUE TO WEOU. 14 wiz pees Seika Pie se eee ene Oe 44 mm. 52 mm. Tip of snout to posterior edge of tympanum....... we OME erat ys Greatest breadth) of ‘head ec6 Sea wes ees ee ee 1 23% Foreleg: from: axilla 3 sot eee ely espe 6 elec cee PS a Es ed Hind leg from ‘vents. cones wee ae ey eee ee 68 4" at ge SCHMIDT, THE HERPETOLOGY OF PORTO RICO 171 _ The most frequent coloration is a grayish brown of varying shade, ‘sometimes reddish, sometimes nearly black, which may be uniform or mottled. In the lighter specimens there is nearly always a dark inter- orbital mark, and in a few the snout is white in front of this, either with a broad transverse white band or completely light to the tip of the snout. ‘There is usually also a dark subcanthal mark, interrupted by the eye, ‘and continued over the ear for a short distance. In a few cases the dorsum is spotted irregularly with vivid white spots. Of one hundred and ninety-four examined, eighteen have a light line beginning at the Fic. 1.—Eleutherodactylus auriculatus (Cope), a 4 A. M. N. Il. No. 10249. A common phase of coloration. Twice natural size. “snout and passing over the edge of the eyelid to the ear, continuing as a broader light dorsolateral band to the thigh. In nineteen specimens there is a sharp median white stripe (compare ‘Fowler, 1918, Fig. 2). Five have a broad median light band, about four times as broad as the more common narrow line. The hind legs are occasionally distinctly yarred, more usually indistinctly barred or uniform. The concealed sur- es of the thighs are often bright pink or red. The venter is usually light and unspotted, occasionally spotted with groups of dark-brown yunctuations. In no specimen were the concealed surfaces of the thighs eticulated with the fine or coarse dark network of 2. antillensis. 172 ANNALS NEW YORK ACADEMY OF SCIENCES Persistent search about the banana plants, under the leaves of which — adults hide during the day, failed to discover the eggs of this species, © and it was not until the writer visited the Luquillo Forest that a single egg-mass was discovered in a basal leaf of an air plant, just at the sur- face of the water in the lower part of the leaf. A large H. auriculatus in the same plant, but not on the same leaf as the eggs, escaped. There are thirty-six eggs, with well-advanced embryos, adhering in an oval mass from which individual eggs are easily detached. The eggs measure 6-8 mm. in greatest diameter, being somewhat elongated in the axis of the embryo. The young of this species are extraordinarily abundant, and it is diffi- cult to understand why the eggs are so infrequently observed. It is possible that at the time of my visit (August to October) the height of — the breeding season had passed. The only previously recorded date of breeding is that observed by Gundlach, May 24 (Peters, 1877, Monatsber. Akad. Wiss. Berlin, 1876, p. 709). Professor Johnson found a mass of eggs on July 8, with embryos at about the Ee same stage as the writer’s, in the same bunch Fic. 2.—Embryo of Hleuwthero- : j eked 4 7 dactylus auriculatus of moss in which the giant female specimen, A. M. N. H. No. 10302. Four mentioned above, was collected. Gundlach eS BAe (loc. cit.) also observed a female sitting on the egg-mass received by him, while Bello y Espinosa (Martens, 1871, Zool. Garten, XII, p. 851) records that in the case observed by him the parent frog remained in the neighborhood of the eggs “as if to guard them.” From these several observations it appears not unlikely that the female does remain in the neighborhood of the eggs until they are hatched, but further observations on this point are desirable. Ruthven (1915, Occas. Papers, Mus. Zool. Univ. Michigan, No. 11), observing the breeding habits of #. cruentus (Peters) in Colombia, found no eyi- dence of such a habit. 3 ’ Eleutherodactylus gryllus, new species Sixteen specimens from Maricao and E] Yunque were collected. Diagnostic Characters Distinguished from Elewtherodactylus awriculatus by a shorter snout less granulate venter, and its minute size. | SCHMIDT, THE HERPETOLOGY OF PORTO RICO 173 Range Taken at El Yunque and Maricao, probably confined to the coffee belt and the wet rain forests above it. Type _ A.M. N. H. No. 10307, 8, El Yunque, near the Forester’s cabin (about 1300 feet), September 30, 1919, Karl P. Schmidt. Description of Type Habitus of Hleutherodactylus auriculatus, but with a distinctly shorter snout, its length equal to the diameter of the eye (in FH. auriculatus the diameter of the eye equals its distance from the nostril), and to the interorbital space; canthus rostralis rounded; nostril one-third the dis- Fig. 3.—EHleutherodactylus gryllus, new species A. M. N. H. No. 10226. Twice natural size. tance from tip of snout to eye; tympanum scarcely distinct, one-fourth the diameter of the eye, its distance from the eye equal to its diameter ; toes without vestige of web; digital disks well developed; first toe as long _as the second; an inner and outer metatarsal fold; vomerine teeth in two oblique patches behind and within the choane; tongue large, slightly nicked behind; skin smooth above, but apparently much more glandular than in #. auriculatus; venter strongly granulate; a large subgular vocal sac. _ Middle of the back, beginning with an interorbital line, dark gray, enclosing a light spot on the occiput; sides and snout lighter, the darker color everywhere consisting of minute black punctations, especially evi- dent on the limbs and throat; venter light. ~~ > 174 ANNALS NEW YORK ACADEMY OF SCIENCES Measurements ify tokssn@nttG-WENG. 25 ins sok ba slicae ancae oe EU oie ere ee 16 mm. Tip of snout to posterior border of tympanum.,),|..0....4.... ..05 eee i es Greatest “orepdthot head's ves Fis sais. Wis’) Fedele Cae cares ee ee 6 : HOPCIGS APO AUDA Sl nee oie a ahe tip eee G-¥ es 5 Sha ae aoe ade a hiaaey ne dd) K: FLING ee’ LTOWY SVEN ss os) ca/cais a wie ssuoleew wha a ais ehpigteus ake ant ngs, ayes eee 24 - MES Tpa adic Se eet access 9 initiate olan dare Gta ge ey caste hh eR MG Ose one. wel glewers et eie eeeaai enn 50a Notes on Paratypes The type is a male, taken singing at night, with the usual pale night coloration. Specimens taken in the daytime (concealed under moss) are — very dark in color and exhibit considerable variation in pattern, two — having a light median dorsal line. In a specimen taken in an air plant (No. 10291) the dorsal dark area is cinnamon brown and the sides bright — pale green, the legs with dark bars; this coloration has been described by ~ Stejneger (1904, Rept. U. S. Nat. Mus., 1902, p. 586) as a variant color- ation of juvenile /. awriculatus. The darker specimens have narrow light — . crossbands on the limbs. The granulation of the venter in the female — specimens is faint, though still evident. This species was found very numerous at Maricao and on El Yunque, ~ singing frequently from trees, at least ten feet’from the ground. On ~ El Yunque specimens were collected in air plants, near the peak, and — under moss on the rocks of the peak itself. The note is a rapid succession of shrill clicks, very insect-like; the chorus sounding not unlike the rapid clicking of a telegraphic instrument. — Were it not for the minute size of the singers and the extremely dis- — tinct note, this species might well be considered the young of #. auricu- latus. I am unable to agree with Stejneger’s supposition that its note is — made by juvenile males of the latter species. ‘The gonads, at any rate, appear to be those of an adult in the specimens examined, differing in form and pigmentation from those of young H. awriculatus of similar size. — Eleutherodactylus locustus, new species A single specimen from El Yunque, just above the Forester’s cabin, — collected September 30, 1919. Diagnostic Characters Size small, snout obtuse, nostril much nearer to the end of the snout than to the eye; tympanum small, indistinct, one-fourth the diameter of the ‘eye, separated from the eye by a little more than its diameter; SCHMIDT, THE HERPETOLOGY OF PORTO RICO ~ PR vomerine teeth in two oblique series, behind and within the choane; toes ' free; digital disks well developed; tibiotarsal articulation reaching the posterior border of the eye; heels overlapping when the legs are placed at right angles to the body; skin rugose above, with scattered round _ tubercles, especially on the eyelid; venter smooth; inner face of thighs finely rugose. f Range ~ Known only from the type locality. : : , , ee Fic. 4.—Hleutherodactylus locustus, new species A. M. N. H. No. 10240, type. Twice natural size. Type A. M. N. H. No. 10240, ¢, El Yunque, near the Forester’s cabin (about 1300 feet), Luquillo Forest Reserve, Porto Rico, September 30, 1919, Karl P. Schmidt. Description of Type Head slightly longer than broad, slightly narrower than the body; snout moderately obtuse, its length anterior to the eye exceeding the interorbital space; nostrils one-fourth the distance between eye and tip of snout from the latter; tympanum scarcely distinct, one-fourth the diameter of the eye, separated from the eye by a little more than its - diameter; canthus rostralis rounded; elbow and knee pressed along the _ side, overlap; heels overlap when the legs are placed vertically to the axis of the body; tibiotarsal articulation reaching the posterior border of the eye; disks of fingers and toes well developed; toes without vestige of 176 ANNALS NEW YORK ACADEMY OF SCIENCES web; inner and outer metatarsal tubercles present; no tarsal fold; first toe as long as the second; vomerine teeth in two linear oblique patches, converging posteriorly, well separated on the median line, behind and within the choane by about the diameter of the choana; tongue large, slightly nicked behind ; skin rugose above, with rounded tubercles; a well- marked mid-dorsal ridge from snout to vent; eyelid strongly rugose; venter smooth (faintly rugose under the lens); thighs shghtly rugose; male with a large subgular vocal sac. Dorsum gray, mottled with grayish brown; a well-defined interorbital dark band; sides of canthus with a dark mark, interrupted by the eye, extending over the tympanum, legs not barred, with dusky markings; venter uniform, light. Measurements ap, OF SHOUT. tO VEHUs Oooo. Leer Soe See wipe es Bb ea 6: ele 19 mm; Mp of snout ‘to posterior border of: tympanum... 4... 0 i. Gate emen 7 eS Greatest ‘breadth, Of WhedG@rcg 6 Soya aie cone A ict a tole enw, cela wie acca 6,5: Koreles strom: axallases oc). to oa ood Sn peeetncle nn phe aesrekene een 12 sh Hind lee. Prom Vvethe oss was kee d AGE, hg ao aa oee a a x 85 x ale a ewe © v8 divtyie'yiaiale eb en w © OS EE Mr SRTETRMCEONA oss etc aie serie pi wibiw a dw a 'e-p wa Moen cee nek Sie es EE POMPEII Soa fehl, Chilis Wins) gl x Weer aieeg Sn ease Rabson em wk oon eS ee ee ee rears ae ett sss ws pct 2g awd W de ae WR Paw y's bw nce are _ Notes on Paratypes The three paratypes are closely similar in size and structural characters to the type. Two have the black subcanthal and shoulder mark outlined with white above. One lacks the dorsal black spots.” The specimen from Maricao was taken singing in herbage along the roadside, together with H. auriculatus and FE. antillensis. Two were taken singing on El Yunque, likewise in low herbage, and the last was found by accident in collecting H. wightmane. The note of this species is a succession of clicks, less shrill and less rapid than in L. gryllus. This species stands in the same relation to E. antillensis as E. gryllus does to #. auriculatus. : Eleutherodactylus wightmane,* new species _ Thirteen specimens of this species were collected at Maricao and El Yunque, near the Forester’s cabin. Diagnostic Characters | Size small, snout pointed; nostril much nearer to the tip of the snout than to the eye; tympanum small, distinct, separated from the eye by about its own diameter; vomerine teeth in two straight series, in the same line, extending as far laterally as the choanex, and about the diameter of a choana behind them; toes free, digital disks well developed ; tibiotarsal articulation reaching the anterior border of the eye; heels overlapping when the legs are placed at right angles to the body; skin rugose above, with elongate folds and ridges; venter rugose; thighs granular. Range Luquillo Forest to Maricao, probably confined to the coffee belt and the wet forests above it. “Named for the author’s wife, Margaret Wightman Schmidt, whose loyal assistance contributed largely to the success of the work in Porto Rico. 182 ANNALS NEW YORK ACADEMY OF SCIENCES Type 7 A. M. N. H. No. 10317, 3, El Yunque near the Forester’s cabin (about 1300 feet), Luquillo Forest Reserve, Porto Rico, September 30, 1919, Karl P. Schmidt. Description of Type Head as long as broad, narrower than the body; snout pointed, its length anterior to the eyes once and a half the interorbital width; nostrils one-third the distance between eye and tip of snout from the latter; tympanum distinct, small, about one-third the diameter of the eye, separated from the eye by a little more than its own diameter; canthus rostralis sharp; elbow and knee pressed along sides overlap; heels overlap when the legs are placed at right angles to the body; Fic. 8.—EHleutherodactylus wightmane, new species A. M. N. H. No. 10220. Twice natural size. tibiotarsal articulation reaching the anterior border of the eye; disks of fingers and toes well developed; digits slender, free; first toe distinctly shorter than the second; no tarsal folds; vomerine teeth in two straight series, separated in the median line, extending laterally as far as the outer border of the choaneze, and about the diameter of a choana behind them; tongue large, slightly nicked behind; skin rugose above, with longitudinal lines or folds, the most distinct of which originate behind the orbits and extend backward about two-thirds the length of the back; a less distinct mid-dorsal ridge from snout to vent; venter and outer face of thighs rugose; a subgular vocal sac. | SCHMIDT, THE HERPETOLOGY OF PORTO RICO 183 _ Brown above, with a black subcanthal line extending over the ear _ half way along the sides; a black spot on each side of the back over the ‘groin; venter uniformly light; a single dark cross-band on the radius; one on the femur, tibia, and tarsus (in line when the legs are folded), and a dark spot on the metatarsus; anterior and posterior faces of the thighs dusky. Measurements ‘Tip weeenout tO vent.........% Se Ci PET So St 9 RE a 20 °: iam, Tip of snout to posterior border of tympanum.................... [67 gear TRE MEL TIMER MEART SW 05.55 tic. a wate wd cin se eben tet asa ee sv evae es (Gs vee ET TILE Seas Da ae Sai ea ee, Per tO rr gla i 0 ESE Se OO ig on ee ee ee 30 i Notes on Paratypes _ In structural characters the twelve paratypes agree closely with the type. Two specimens are light gray, instead of brown, with only indica- tions of the black spots; in most specimens the postocular dark streak is ‘broken up into a series of spots; one specimen is light brownish gray on each side, the area between sharply darker; the bars on the legs are dis- tinct in all specimens. | The plaintive, diminuendo note of this small species is one of the most characteristic sounds in the amphibian chorus of the Luquillo forest. Its song consists of a series of six or eight whistled notes, each slightly louder in pitch and a little fainter than the last. It sings habitually on the ground or in the lowermost leaves of plants. It is particularly diffi- cult to locate its position from its song, partly because it is usually well concealed, partly on account of the peculiar ventriloquy of its voice. Eleutherodactylus richmondi Stejneger Eleven specimens of this species were collected at El Yunque, between the Forester’s cabin and the peak. This species is probably distributed throughout the virgin forest of the Luquillo Reserve. It should be looked for in the high forest south of Jayuya. Its relations with FH. lentus of St. Thomas and £. weinlandi of Hispaniola add to the evidence of former land connections of the Virgin Islands and Hispaniola with Porto Rico. _ Like the larger series examined by Stejneger, the present specimens are extremely uniform in structural characters and in coloration. The only variation noted is the occasional lightening of the chestnut color —_—--—_—_ ——_—_——- >) 184 ANNALS NEW YORK ACADEMY OF SCIENCES are quite different in this species from the other Porto Rican species of the genus: No. 10233 Tp Ob) SHOWE BOM Y CMTS se 2 hisio ea a ota el ace a's hoe waist arin ee, cn eeu lias oe 32 mm. Tip of snout to. posterior border of tympanum... ....00.... 00. see Le Greatest breadth: of head... 5... ps acide are uetels tine bea ech eee Pap eee Horeles: from, axallas. os. os bs eee mete ginger Buscar ee pels eae Oe ale pot hey Hind lee Trent vent... s:.:)-teshterscere a teers ih goa ee AG Pee Fig. 9. A. M. N. H. No. 10237. Twice natural size. Eleutherodactylus richmondi Stejneger Two extremely small specimens, measuring 9 and 11 mm. respectively, — probably are recently transformed. They are colored like the adults. REPTILIA Spherodactylus Wagler Spherodactylus macrolepis Giinther Spherodactylus macrolepis monensis Meerwarth, 1901, Mitt. Naturh. Mus. Hamburg, XVIII, p. 20. Spherodactylus monensis Stejneger, 1904, Rept. U. S. Nat. Mus., 1902, p. 607. ! Barbour, 1914, Mem. Mus. Comp. Zo6l., XLIV, p. 270. . Fal it SCHMIDT, THE HERPETOLOGY OF PORTO RICO 185 ‘Spherodactylus grandisquamis Stejneger, 1904, Rept. U. S. Nat. Mus., 1902, p 602, figs. 46-52. Barbour, 1914, Mem. Mus. Comp. Zo6l., XLIV, p. 270. The following localities are represented by forty-five specimens in the collection: Aibonito, Bayamon, Cataho, Coamo Springs, Ensenada, Mari- cao, El] Yunque, and Mona Island. This species is found on Mona Island, throughout Porto Rico, and on most of the Virgin Islands ( Vieques, St. Thomas, St. Croix, Tortola, Virgin Gorda, Anegada). Stejneger, with specimens from only two localities in Porto Rico (Luquillo and Ponce), described the Porto Rican and Vieques specimens as distinct from the Virgin Island form, as well as from that of Mona Island. He surmised that it was confined to the lowlands, whereas the present series proves that it reaches an altitude of at least two thousand feet. - Barbour (1917, p. 98), after examining a considerable series of Spherodactylus macrolepis from the Virgin Islands, expresses a measure of doubt as to the distinctness of S. grandisquamis. Stejneger separates 8. grandisquamis and 8. monensis from 8. macrolepis solely on the size | of the scales, which he gives as 34-38 about the body in 8. grandisquamis, B46- -48 in S. monensis. In the series from Eorto Rico under consideration _ the variation is as follows: Benles about the body... ..o0.5¢h6% 32—36—40 44 48— 5 2— 56 Wumber of Specimens... . 60... es: sig oid Ts ea! aaa Ai © bare In five specimens from Mona Island the number of scales varies from 44-52. As S. macrolepis is intermediate between S. grandisquamis and S. monensis, it is evident that the variation in the present series includes all three supposed forms. There is probably a somewhat different range of variation on the several islands, but the extremes are certainly included in that of the Porto Rican series. Reproduced tails have a much widened series of median ventral scales. An egg, probably of this species, was found Gace a log at Aibonito, “August 21, 1919. It is white, discolored by stains, with a hard and smooth shell, 6 x 4.5 mm. Anolis Daudin Anolis cuvieri Merrem _ Eleven specimens of this species were collected at Aibonito. Anolis cuviert has been taken at Aibonito, Catalina Plantation (El Yunque), Hlumacao, Luquillo, Mayaguez, and Utuado. It is probably not found in the arid southwestern corner of the island, but ranges quite generally over the remaining part of Porto Rico. It is recorded from Vieques and 186 ANNALS NEW YORK ACADEMY OF SCIENCES Tortola of the Virgin Islands. Its absence from the other Virgin — Islands is probably due to difference in the habitat conditions. It is — nearly allied to Anolis ricordw of Hispaniola. — ; There is little variation in this series. In No. 13234 the tail crest is unusually high, fully as high as in A. ricordw of Hispaniola, but the | scale characters which distinguish cuviert from ricordii are perfectly — constant. . Seven out of eight stomachs examined contained the remains of large i beetles; one, a large phasmid; one, remains of heteropterous bugs; and one, a mass of skin of Anolis cuviert (doubtless its own). The boys say that it eats berries and fruits, and in the coffee plantations it is said to eat coffee berries. It seems probable that vegetable matter forms only a small proportion of its food, as in Anolis cristatellus. Anolis cristatellus Duméril and Bibron The following localities are represented by three hundred specimens in the collection: Adjuntas, Aibonito, Bayamon, Cataho, Coamo Springs, — Ensenada, Maricao, Mayaguez, Salinas, San Truce, Desecheo Island, Mona, Vieques, and Culebra. This species ranges everywhere in Porto Rico. It occurs also on Mona and Desecheo Island, to the west, and ex- tends through the entire Virgin group to the east. I do not regard the ~ records of this species from Santo Domingo as valid. A nearly allied form is found in the Turk’s Islands (Anolis albipalpebrahs Barbour). Stejneger regarded the Anolis of Mona Island as a species distinct from — A. cristatellus, differing in having larger scales on the head; hence fewer loreals and fewer scales between the occipitals and the semicircles; in having a much higher tail crest, and a somewhat peculiar coloration. I cannot agree in this separation. Specimens from Ensenada and Coamo Springs agree exactly with those from Mona, while A. cristatellus from Culebra Island has an even higher caudal crest than those from Mona. — The coloration of the Mona specimens taken on limestone is not ordinarily seen in Porto Rican cristatellus, but specimens taken on limestones at Ensenada, Salinas, and Coamo Springs are similarly colored. Ordinary cristatellus with low tail crests occur in the same area, and it is obviously impossible to separate them. The species does differ somewhat on the various islands, but the variation curves overlap too greatly to warrant even subspecific distinction. The number of scales between the occipital and the semicircles varies as follows in forty specimens respectively from Vieques and Mona Islands: SCHMIDT, THE HERPETOLOGY OF PORTO RICO 187 Number of scales between occipital and semicireles.......+.. Lovee oS mumber of specimens, Mona Island............0...ceeeeeeees 4: 18-8 “Number of specimens, Vieques.............. ves. e eee e sence 5 ie! laa aco The vertical rows of loreals in the same series are as follows: q a Loreals.......... Aen ae ea an wv we Dla ee 2 es we an aS a SURREY AMS «bls tore aac wb Oe 4 dies (eae OTE eee ee ae Pe Rs ett tue ee Ercems ly ial ae atstinnenets Te, 33a 8 . In the present series of Porto Rican specimens, adult males which wholly lack the tail “fin” are frequent, and such specimens are even more frequent in Vieques. Thus, of thirty-nine males collected in Vieques, none have a high continuous “fin” like those of Culebra or Mona, twenty- seven have a low serrated crest, about one-third as high as the diameter _ of the tail, and twelve lack the crest entirely, having merely a compressed tail with a denticulate row of dorsal scales. This is evidently the con- dition referred to by Reinhardt and Luekten (1863, Vidensk. Med. : -naturh. For. Kjgbenhavn, p. 249), whose comment was inexplicable to "Stejneger (1904, p. 640) because he lacked a sufficient series from Vieques. In going from Vieques to Culebra, the difference between the tail crests of the males is very striking, and if they were not linked by Porto Rican specimens they would certainly be regarded as distinct forms. ‘Thus, out of twenty Culebra males, only four have a crest as low as the highest found in the Vieques specimens, and in the remaining sixteen ‘it varies from a height equal to the vertical diameter of the tail to twice the diameter. Evidently we have an excellent example of the beginning of the process of differentiation through isolation on islands of this plastic species. The specimens from Desecheo present no peculiarities. _ Anolis cristatellus reaches an altitude of at least two thousand five ‘hundred feet, being associated with Anolis pulchellus on the deforested hills near Maricao. It is evident that the differences in the distribution _of this species and A. gundlachi are due not to altitude, but to habitat conditions, of which light seems to be one of the determining factors, _A. cristatellus being the species of open fields and roadsides, A. gundlachi of the thickly planted coffee plantations and of the forests. The examination of one hundred stomachs yields the following in- formation ‘as to food habits: Empty, 22; unidentified insect remains, 15; beetle remains, 20 (larva and adults; a species of Diaprepes very abun- dant) ; Orthoptera, 16 (cockroaches, grasshoppers, and a single cricket -and mantis) ; ants, 10; caterpillars, 9; bugs, 5 (mostly heteroptera, one large cicada) ; flies, 3; spiders, 3; vegetable matter, 9 (mostly brightly colored seeds) ; vertebrates, 2 (Anolis sp.). 188 ANNALS NEW YORK ACADEMY OF SCIENCES The eggs are two or three in number, about 10 x 6 mm., uniformly — oval, the surface white and striate. They are frequently found under | the edges of logs or stones, or in debris about the base of banana plants. ~ Anolis gundlachi Peters Forty-eight specimens of this species were collected at the following | localities: Adjuntas, Aibonito, Maricao, and El Yunque. This species — | is very distinct from A. cristatellus, but is obviously directly related to | that species. Its range and habitat are much more restricted and ~ the amount of variation is accordingly smaller. In the present series the height of the tail crest (at its highest point) reaches a maximum | of three times the diameter of the tail at the same point. , Anolis stratulus Cope The following localities are represented by fifty-eight specimens of this species in the collection: Aibonito, Coamo Springs, Ensenada, Maricao, | El Yunque,:and Vieques and Culebra Islands. The distribution of | Anolis stratulus is closely similar to that of Anolis cristatellus, occurring on Porto Rico, Vieques, Culebra, St. Thomas, Tortola, and Jost Van Dyke. It is not found on Mona Island, and has not been recorded from St. Croix, where it might logically be expected to occur. The series under examination shows only shght variation. The ma- jority of specimens have the supraocular semicircles in contact. One | (No. 13282) has only a single row of scales between the occipital and | the semicircles. In recently hatched specimens the dorsal markings are invariably indistinct. | | The examination of twenty-five stomachs indicates that ants form a much larger proportion of the food than in A. cristatellus. The contents are classified as follows: Empty, 3; unidentifiable insect remains, 4; ant © remains, 12; beetle remains, 5; spiders, 2; cockroach, 1; earwig, 1; flies, 1; lizard skin (doubtless its own), 1. | Anolis evermanni Stejneger The following localities are represented by thirty-seven specimens in the collection: Adjuntas, Aibonito, Maricao, and El Yunque. This species is confined to Porto Rico and does not appear to be especially related to the green Anolis of Hispaniola (A. chlorocyanus). It appears Porto Rico it is most abundant in the coffee belt, but reaches the coastal plain at Rio Piedras and doubtless occasionally elsewhere. SCHMIDT, THE HERPET'OLOGY OF PORTO RICO 189 As in A. stratulus, the scale between the supraciliaries and the supra- orbital semicircles, anterior to the supraorbital granules, is remarkably constant. It is double on one side in only one specimen out of thirty-one examined. The semicircles may be broadly in contact (3 specimens), narrowly in contact (9), or separated by a single row of scales (19). The ‘scales between the semicircles and the occipital vary from two to four. Anolis mayert from the Virgin Islands was compared in the original description with Anolis cuviert and Anolis cristatellus (Fowler, 1918, Papers Dept. Marine Biol., Carnegie Inst., XII, p. 8, Fig. 4), chiefly because of the presence of small granular scales interspersed between the larger dorsal scales. On examination with sufficient magnification, both A. cristatellus and A. evermanm prove to exhibit this character. A. _mayert is therefore not particularly related to A. cuviert and is in fact intermediate between A. cristatellus and A. evermanni, having the two scales bordering the supraocular granules anteriorly of A. cristatellus, while it is closely allied to A. evermanni by its habitus (especially the form of the head and tail), the larger scales, and the uniform (green) coloration. It is remarkable that no other specimens of this species have | appeared in the numerous collections from the Virgin Islands. The results of the examination of the contents of twenty stomachs are as follows: Empty, 3; beetle remains, 11; wasps, 2; ants, 1; caterpillars, 1; spiders, 1; skin of Anolis (doubtless its own), 2; juvenile Anolis —evermanni, 1. Anolis pulchellus Duméril and Bibron The following localities are represented by eighty-seven specimens in the collection: Aibonito, Catahfo, Coamo Springs, Ensenada, Maricao, Mayaguez, San Turce, Culebra and Vieques Islands. Anolis pulchellus is recorded from nearly all of the Virgin Islands, in- eluding Anegada and St. Croix. Except for its absence from Mona Island, it has therefore the same distribution as Anolis cristatellus. The number of loreal scales in a vertical row is usually four (five or ‘six in A. krugt) ; in eighty-five specimens, sixty-nine have four loreal rows, fifteen have five, and one has six. The scales separating the occipital from the supraorbital semicircles number one in one specimen, two in twenty-nine specimens, three in fifty-one, and four in four. The semi- circles are in contact in seventeen specimens, separated by one scale row in sixty-six, and by two scale rows in two. Stejneger supposed that Anolis pulchellus was confined to the coastal plain area, rarely going above five hundred feet in altitude. In the course 190 ANNALS NEW YORK ACADEMY OF SCIENCES of the present survey it was found to be abundant everywhere, up to an altitude of at least two thousand feet, but strictly confined to open fields. — Anolis krugi Peters The following localities are represented by sixty-two specimens in the collection: Adjuntas, Aibonito, Coamo Springs, Maricao, and El Yunque. — Anolis krugi is confined to Porto Rico. In Porto Rico it is confined — largely to the coffee belt, extending beyond it only where similar habitat — conditions occur. It is directly related to the more widely distributed Anolis pulchellus and is probably derived from it. The specimens re- corded from Guanica by Fowler (1918, Papers Dept. Marine Biol., Carnegie Inst., XII, p. 11) prove on re-examination to be A. pulchellus. In sixty specimens, the number of loreal scales in a vertical row is © four in one specimen, five in thirty-four, six in twenty-three, and seven in two. The number of scales between the occipital and the supraorbital — semicircles varies from one to six—one in one specimen, two in eighteen, three in twenty-five, four in thirteen, five in two, and six in one. The supraorbital semicircles are in contact in two specimens, separated by a single scale row in thirty-four, by two scales rows in nineteen, and by three in five. ‘This species is often difficult to distinguish from A. pulchellus without direct comparison; the color of the dewlap in life, orange instead of crimson, is distinctive. In alcoholic specimens the narrower band of enlarged dorsal scales is the most satisfactory character for separating the two. Other characters are at best comparative, useful — only for a series of specimens. — Stejneger distinguished Anolis krugi as characteristic of the inter-— mediate altitudes, from five hundred to fifteen hundred feet. The speci- mens in the present series from Coamo Springs are from an altitude of less than three hundred feet, while specimens from Aibonito reach an _ altitude of at least two thousand feet. The specimens from Coamo Springs supply the clue to the determining factor in the distribution of the species, for at that locality it was abundant among the ferns and vines of the moist, dark gorge back of the bath-houses and was found nowhere else. At Aibonito and Maricao, Anolis pulchellus was found on the bare hilltops or in open fields, while a few steps within the borders of the coffee plantations only A. krug: was to be found. Moisture and shade, therefore, are the habitat requirements of Anolis krugi. Anolis crista- tellus and Anolis gundlachi have an exactly parallel distribution. SCHMIDT, THE HERPETOLOGY OF PORTO RICO 191 Anolis pencensis Stejneger Thirty-eight specimens of this species were collected at Coamo Springs and Ensenada. This very distinct species of Anolis is confined to Porto Rico, and specifically to the arid southwestern area from Coamo Springs to Ensenada (and probably to Cabo Rojo). Anolis poncensis is a highly unique species, not only in its lepidosis, but in the extremely small size of its throat fan, scarcely one-third as large as that of A. pulchellus or A. krugt when extended. There is little variation in the present series, which is much the largest hitherto ex- amined. The coloration described by Stejneger is characteristic and con- stant. The females invariably have a broad mid-dorsal band. The loreal rows in a vertical line are three in eighteen specimens, four in twenty. _ The scales between the occipital and the supraorbital semicircles are none in two specimens, one in twenty-one, and two in fourteen. The scale rows _ separating the supraorbital semicircles are none in thirty-two specimens, one in six. This species was found associated with Anolis cristatellus and with a rare A. pulchellus, at both Coamo Springs and Ensenada. Broadly speaking, it replaces A. pulchellus in the southwestern part of the island, inhabiting fences and grazing land much as A. pulchellus does in the remaining part of the island. A few specimens were found on the arid cactus-covered hilltops about Ensenada. Near Coamo Springs this Species occurred in colonies, sometimes a mile or more apart. Cyclura Harlan Cyclura stejnegeri Barbour and Noble One specimen of this species was collected on Mona Island. This single specimen is a very old male with the irregular development of the large tubercular scales of the head characteristic of old specimens of this group. The nasal is separated from the rostral on one side by a space filled with very small scales; on the other by a large tubercular shield. A third “comb” is plainly distinguishable on the third toe. The scales _ of the reproduced tip of the tail are not arranged in verticils. The measurements as as follows: NR t se ar eas ee Vike cle k Wocta pic ais cee'd e 4's osec dese 127 TREN te GRD Sg hire 1, ida Ae galas gible-«)sk Ss Waele + ote os rept aes 79 Tears Pct oe Me be OR Bi Ss a Ls oe n'e «ies wales 173 RS Ske TERETE SRN RIE Oe SE gE po ite 192 ANNALS NHW YORK ACADEMY OF SCIENCES In spite of the separation of the nasal shield from the rostral, I have retaiged the name stejnegeri, as it may well be the case that the young of the three related species, cornuta, nigerrima, and stejnegert, are well dis- tinguishable, while in the adults the characters are obscured. In other respects it accords well with the previously described specimens from Mona. Additional material of cornuta, however, is required to establish satisfactorily the status of the forms on Mona and Navassa. Celestus Gray Celestus pleii (Duméril and Bibron) Seven specimens were collected at Aibonito. This species is confined to Porto Rico, where it is apparently rare and of local distribution. The present series is so uniform in scale characters as to suggest that they are directly related. The proportion of the length of the forelimb — to that of the body varies between 12:100 and 15:100. The scales about the body are 34 in one, 35 in one, 36 in four, and 38 in one. The two female specimens contain respectively one and three well ad- — vanced embryos. The egg measures 18 x 11 mm. The completely formed embryo rests on a very large yolk mass. The head and legs of the embryo are proportionately larger than in the adult, while the tail is shorter. Ameiva Meyer Ameiva exsul Cope The following localities are represented by fifty-two specimens in the ~ collection: Coamo Springs, Ensenada, Palo, Seco Point, San Truce, and Culebra Island. This species reaches a large size, apparently much ex- © ceeding half a meter, but the larger specimens are exceptionally wary and IT was unable to secure them. The largest seen was on Culebra Island. In nearly all the specimens examined an additional row of ventral plates on each side is enlarged to a varying degree, in some cases to such an extent that there are distinctly twelve longitudinal rows of ventrals. The common report in Porto Rico that the “iguana” eats the shoots of — young corn appears to be supported to a degree by an examination of © stomach contents. Of twenty stomachs examined, one was empty; eleven contained vegetable matter, chiefly large numbers of red-coated seeds; five, unidentifiable insect remains ; two, crickets ; three, small crabs; three, — eggs of a lizard; one, tail of a large Anolis cristatellus; and six, parasitic worms. SCHMIDT, THE HERPETOLOGY OF PORTO RICO 193 Ameiva alboguttata Boulenger Forty-two specimens were collected on Mona Island. This species is confined to Mona Island, where it is abundant on the low terrace to the west and south. Ameiva alboguttata is*extremely close to Ameiva easul, but may be distinguished by the more spotted dorsum. ‘The Mona Island form does not exhibit the tendency to enlargement of an additional row of ventral plates, one specimen having only eight longitudinal rows of ventrals (No. 13739). _ ‘The results of the examination of twenty stomachs are as follows: Empty, 4; vegetable matter (chiefly red-coated seeds), 8; unidentifiable insect remains, 3; beetles, 3; crickets, 2; land snails, 2; Anolis crista- tellus (juv.), 1. Ameiva wetmorei Stejneger Twenty-seven specimens were collected from Ensenada. This species, hitherto known only from two specimens, appears to be confined to the region near Ensenada. It probably ranges westward toward Cabo Rojo and eastward toward Ponce, on the limestone hills. Amewa lineolata, its relative in Hispaniola, appears to be similarly confined to the more arid _ parts of that island, and arid or semiarid conditions prevail also on _ Great Inagua and St. Croix, each of which is inhabited by a related _ species. These four species form a highly interesting group of Ameivas, _ characterized by the oblique scales of the tail, a distinctive habitus, and a lineolate type of coloration. In the present series the prefrontals are broadly in contact in twenty- one specimens, meet at a point in one, and are separated by a suture between the frontal and frontonasal in three. The number of supra- ciliaries varies from five to seven; normally six. The interparietal is horizontally divided in one specimen. There are usually two or three transversely enlarged postoccipitals. On the whole, there is a remark- ably small degree of variation. The measurements of a male and female specimen are: Ay MON. EL. No. 13821 @ No. 13828 9 ' Total length (tail reproduced at tip)............ 169 mm. 147 mm. EE alec e Ah a) ccohatate Bip eek ea GA © ns pie Ga e 52 - 45 Es Re PANOMEES fo Sc hacar yea obs wie ko ncb o b e weve 12. Orres ik s MRM CR SNORE 2 pins A ER Ds alec ba ake was eo Bab. ? a EMT crate he RPat es , a Ne Shadi ass apa wceimseiane wdie’d » 16 a“ 14 = Sa SSS Rs 9 ee 30 as 26 2 194 ANNALS NEW YORK ACADEMY OF SCIENCES This species was found only on or near the tops of the lmestone hills back of Ensenada, associated with a few Ameiva exsul. Amphisbena Linné Amphisbena ceca Cuvier Eighteen specimens of this species were collected at Aibonito, Bayamon, and Rio Piedras. This species is confined to Porto Rico, with a related species in the Virgin Islands (A. fenestrata) and another in Hispaniola (A. mann). , The variation in the present series falls well within the hmits estab- lished by Stejneger. One specimen has a small supraocular plate on each side. When killed in formalin, the head is bent abruptly to one side, in- dicating apparently a special development of the muscles of the neck, which doubtless is of advantage to the animal in burrowing. 'The largest specimen measures 233 mm.; tail, 18 mm. All of the specimens were found burrowing in the ground, most of them uncovered by cultivation. One-was found about three inches be- neath an ant’s nest, under a log, while digging up the eggs of Leimadophis. Three eggs were found—one beneath a termite nest, the other two under the log where the above-mentioned adult was dug up. The largest egg measured 42 x 11 mm. Mabuya Fitzinger Mabuya sloanii (Daudin) The following localities are represented by seven specimens in the col- lection: Bayamon, Ensenada, and Mona and Culebra Islands. This— species ranges from Mona Island through Porto Rico and the Virgin Islands. Barbour (1916, p. 219) refers two specimens from Turk’s Island, in the southern Bahamas, to this species, and it seems probable that the Mabuya of Hispaniola is also referable to the same species. With seven specimens before me—three from Culebra, three from Porto Rico, and one from Mona—I am unable to find differences cor- — responding to the separate localities, other than the difference in color described below. In all specimens there are two pairs of chin shields in contact behind the unpaired postmental. The prefrontals are narrowly — or widely separated by a suture between the frontal and the frontonasal. The supraoculars are three on one side in one specimen. One specimen | has three large occipitals on one side. The scales about the body are thirty-two in the specimens from Culebra and Mona and in one from Porto Rico, thirty in the remaining two. SCHMIDT, THE HERPETOLOGY OF PORTO RICO 195 _ ‘The coloration is highly interesting. The three specimens from Porto _ Rico agree with the description of Stejneger (1904, p. 611) in the pres- ence of a narrow black border above the dorsolateral light line. In the specimens from Culebra this is increased anteriorly to include the whole of the .head, neck, and shoulders, leaving, however, a sharply defined ~ median light line from the frontal to the shoulders, where it merges into the dorsal color. This pattern is approximated also in the specimen from _ Mona Island. It is evident that the type of Huprepes semiteniatus Wieg- - mann described by Stejneger (1904, p. 610) corresponds accurately with _ the Culebra specimens. It is therefore possible that the Porto Rican form may be sufficiently distinguishable to merit specific or subspecific designation, in which case sloanw would be restricted to the form in the _ Virgin Islands (including Vieques and Culebra) and M. nitida Garman would be applicable to the Porto Rican and Santo Domingan form. Jn _ view of the close approach of the Mona specimen to those from Culebra, I prefer to retain, for the present, the use of sloani for the entire series. _ The measurements of the only specimen with a complete tail are as follows: A. M. N. H No. 14007 et ea ce ik 0 eile sate gd) va's Cheyne myn, # oaUe Siento a Seed bral alee d wpacay 180 mm NT rc ered aa. Ou, ie che Gites wah don vimin ave P alalve oo tye bwin aces off MITES PGE Ree rote, fo oy Crinkle Ss Bg. wm a caSecd ow erm a yaa Mace Boel Kom bias suns chs petite ERNE I ae Se. hs a iB ails Amc avin e Mw alo Cela die leas ee bowed s 405. %° PE rR See Tt ee Ee eae eds oat 7S PRP aerate erat hb 6s ee Ran cele Chap ielei scat sw eik i a The largest specimen (from Culebra) measures 90 mm. from snout to Byvent. 3 Typhlops Oppel Typhlops richardii Duméril and Bibron Typhlops richardii Duméril and Bibron, 1844, Erpetol. Gen., VI, p. 290. ., Typhlops lumbricalis Stejneger, 1904, Rept. U. S. Nat. Mus., 1902, p. 684, figs. 141-144. Typhlops lumbricalis (part) Barbour, 1914, Mem. Mus. Comp. Zool., XLIV, p. 322. Nineteen specimens of this species were collected: at Bayamon. The common species of T'yphlops in Porto Rico has been referred to T. lumbricalis by all authors since the publication of Boulenger’s “Cata- logue of Snakes” (1893). The large series now before me appear to ‘warrant a distinction of the Porto Rican form, for which T have used the 196 ANNALS NEW YORK ACADEMY OF SCIENCES name applied by Duméril and Bibron to the Typhlops from St. Thomas, on the ground that it is logically likely to be conspecific with the Porto Rican form. In its more elongate form and greater number of scales from snout to vent, the description of 7. richardw apples fairly well to the series from Porto Rico. Typhlops lumbricalis is reported from all of the Greater Antilles and from a large number of the Lesser Antilles. Being unable to examine specimens from the Lesser Antilles, | am unable to form an opinion as to the status of the form found there. The Linnean description of 7’. lumbricalis is said by Duméril and Bibron to be taken from the Jamaican Amphisbena argenta of Browne. Not having Jamaican specimens for comparison, I have compared the Porto Rican series with the specimens from Cuba in The American Museum of Nat- ural History. In fourteen specimens examined in detail, the total length varies from 216 to 310 mm.; average, 266 mm. The largest specimen available from Cuba measures 244 mm., the average length of nine specimens is 203 mm., and the specimen selected by Barbour for description in the “Herpetology of Cuba” (Barbour and Ramsden, 1919, Mem. Mus. Comp. Zool., Cambridge, XLVII, p. 185) measures only 182 mm. It appears, therefore, that the Porto Rican and Cuban Typhlops are distinctly differ- ent in adult size. The ratio of the body diameter to total length is only slightly different in the two series, 34 to 44 in the Porto Rican, 27 to 38 in Cuban. The number of scales about the body is 22-20-20 in seven specimens, 22-20-18 in seven, in the Porto Rican series; the reduction to 20 scale rows occurring only a little anterior to the middle of the body. In the Cuban series the scale formula is 20-20-18 in six, 20-18-18 in three specimens. The number of scales counted on the mid-dorsal line from snout to tail spine ranges from 365 to 415 in the Porto Rican specimens and from 270 to 325 in the Cuban. (The Cuban specimen described by Barbour has been reéxamined at my request by Mr. Emmett R. Dunn and is found to have between 320 and 325 scales on the mid- dorsal line.) In spite of the relatively small series of Cuban specimens at my disposal, it seems unlikely that the range of variation of a larger number would be greatly different. The Porto Rican specimens are darker in color, and, with a single ex- ception, the tail is marked with a white ring. In the specimen described by Stejneger (1904, p. 685), as well as in the exception here noted, the white ventral color forms a prominent notch on the side of the tail, indi- cating the existence of the tendency to form a ring. No such notch or ring is found in Santo Domingan or Cuban specimens. | SCHMIDT, THE HERPETOLOGY OF PORTO RICO 197 The differences, then, between the Porto Rican and the Cuban T'yphlops may be summarized as follows: Porto Rican Cuban _ Average length of adult...... Greater than 250 mm. Less than 250 mm. Seales about the body....... 22-20-20 or 22-20-18 20-20-18 or 20-18-18 Seales from snout to tail spine. 365-415 270-325 Soe eer ee With white ring or Without white ring notch or notch The specimens of the present series were found during cultivation on the farm of Mr. B. A. Wall. The single specimen secured by me per- sonally was burrowing in the loose earth around an old stump, in which both Typhlops and Leimadophis eggs were found. _ Three eggs of this species were found in the soil about the same stump, j containing well-developed embryos. The egg is elongated, like a slightly bent cylinder with rounded ends, with a perfectly smooth, white surface. The embryo measures 98 mm. in length and 3 mm. in diameter. The smallest hatched specimens found measure 114 mm. _ Three of the smallest specimens in the collection are in every way like the adults, except that they are pale grayish white. This appears on examination to be caused by the opacity of the skin, which is nearly ready to be shed, probably for the first time. An adult Cuban specimen in the collection has the same appearance, and the underlying skin proves to be normally colored. Some of the cases of supposed albinism in 7. /uwmbri- calis may be due to this appearance. Typhlops rostellatus Stejneger Eleven specimens of this species were collected at Aibonito and Baya- mon. This species is confined to Porto Rico, where it proves to be widely _ It is readily distinguished from 7. lumbricalis by its nearly uniform coloration above and below and the sharply defined white subcaudal spot. There is little variation in the present series. The scales about the body _ The measurements of the largest specimen are as follows: AL MeN: Fi: No. 13345 ERS REISE SERS Sat Oat a tO A "goer a 205 mm. 198 ANNALS NEW YORK ACADEMY OF SCIENCES Leimadophis Fitzinger Leimadophis stahli Stejneger T'wenty-four specimens of this species were collected at Aibonito, Baya- mon, and Ensenada. Leimadophis stahli is confined to Porto Rico, re- placed by a vicarious form, L. exiguus, in the Virgin Islands, and closely — related to the Hispaniolan L. parvifrons. The range in number of ventral plates is slightly greater in this series — than in Stejneger’s—-146-166 in twenty-three specimens. The subcaudals range from 83-94. The sexes are scarcely distinguishable by these char- acters. ‘The tail length varies from .29 to .34 of the total length (.29-.31 in 2, .382-.34 in ¢ specimens). The scales about the body are uniformly — 19-19-17. The lower labials are nine (eight in the original description). Freshly hatched specimens show the color pattern most. distinctly, espe- cially the median black marking on the head. The largest specimen, a ~ female, measures 580 mm.; tail, 178 mm. Kiggs of this species were found in three places: under a log in a pas- ture and under an old termite nest in a coffee plantation at Aibonito and — in the loose soil under a stump at Bayamon. One lot contained seven eggs, one thirteen, and one forty. Six well-developed eggs were found in the adult female staying with the largest number. The eggs in this place were in three lots: eighteen old and discolored, in two clusters; six loose, somewhat different in appearance; and two clusters of six and ten eggs very fresh and white. Examination of the eggs showed that they con- tained embryos at at least three stages, the fresher eggs having scarcely — begun development, the oldest containing embryos nearly ready to hatch. The eggs found under the termite nest were also in two clusters—one of seven eggs, with advanced embryos, the other of six, with no apparent development. The older eggs are shghtly larger, ranging from 21 to 25 mm. in length and from 12 to 15 mm. in diameter. The surface is finely — striate, very white in the fresher specimens. It appears that the adult females of this species take up a location from which they do not wander far, and in which they lay successive batches of eggs, from six to eighteen — (?) in number. The largest “nest” contained the remains of still older eggs, which were either infertile or from which the young had hatched. The eggs are laid in clusters of six to ten, the individual eggs adhering firmly to the mass. The rate of reproduction is evidently fairly rapid. SCHMIDT, THE HERPETOLOGY OF PORTO RICO 199 Alsophis Fitzinger . Alsophis antillensis (Schlegel) Alsophis anegade Barbour, 1917, Proc. Biol. Soc. Wash., XXX, p. 102. _ Two specimens were collected at Coamo Springs. This species has not hitherto been recorded from Porto Rico, although there is an older, ques- tionable record from Haiti. Its presence in Porto Rico, together with that of Eleutherodactylus antillensis, diminishes the difference between the Porto Rican fauna and that of the Virgin Islands. _ The identification of these two specimens with this species removes the element of geographical distinctness from the allied A. portoricensis. The male specimen has only seventeen scale rows, and so might be iden- tified with A. portoricensis, were it not that the coloration of both is nearly typical of A. antillensis, while the female has nineteen scale rows at mid-body. In view of the higher number of ventral plates and the distinct coloration, I prefer to retain portoricensis and antillensis as distinct species. _ These specimens agree closely in coloration with the color variety de- scribed by Barbour from Anegada, and as I do not wish to admit of a discontinuous distribution of A. anegade, it seems best to include both Porto Rican and Anegadan specimens with A. antillensis. _ The measurements and scale characters are as follows: A. M.N. H. No. 13305 3 No. 133806 Q ee PENG Ct eh Sa naw ga 0 kre Se 707 mm. 820 mm. TN fA eT ihe te cing 2 i oiaiin atSid wale, ds ow 0 ais aay) * tS i apd aia ALY Oe Ro ee a Ses NSE ne a ae 184 “* 185.-* NE eee OD Ce St ais bce ob 134°. Dis ab is NEES Neate ohraia Servite 2 > pie Kees od 6 ob wae iv. 17-17-15“ 17-19-15 “ Alsophis portoricensis Reinhardt and Luetken _ Four specimens of this species were collected, at Adjuntas and on Mona Island. This species is confined to Porto Rico and Mona Island, its “nearest relatives being A. melanichnus in Hispaniola and A. antillensis in Porto Rico and the Virgin Islands. The two specimens from Adjuntas are perfectly typical in coloration, the dorsal scales and ventral plates being heavily bordered with black. In the two Mona Island specimens the black is arranged as irregular transverse markings, not confined to the borders of the scales. There loes not seem to be any scale character distinguishing them from typical a 200 ANNALS NEW YORK ACADEMY OF SCIENCES portoricensis. The four specimens fall within the limits of variation established by Stejneger in every respect. The two from Adjuntas have the dorsal scale formula of 17-17-14 instead of 17-17-15, as in the Mona Island specimens. The stomach of one of the specimens from Mona contained the remains of two Ameiva alboguttata, and that of the other contained a tail of the same species. LITERATURE BARBOUR, THOMAS’ 1914. A contribution to the zobgeography of the West Indies, with especial reference to.amphibians and reptiles. Mem. Mus. Comp. Zodl., XLIV, pp. 209-359, Pl. I, text-fig. 1. . ; 7 1915. Recent notes regarding West Indian reptiles and amphibians. Proc. Biol. Soe. Wash., XXVIII, pp. 71-78. . 1916. Additional notes on West Indian reptiles and amphibians. Proc. Biol. Soc. Wash., X XIX, pp. 215-220. 1917. Notes on the herpetology of the Virgin Islands. Proc. Biol. Soc. Wash., XXX, pp. 97-104. 1919. Herpetological notes. Notes on Celestus. Proc. New England Zool. Club, VII, pp. 11-13. ae 1919a. A new rock iguana from Porto Rico. Proc. Biol. Soc. Wash., XXXII, pp. 145-148, Pl. I. BarBour, THOMAS, and NOBLE, G. KINGSLEY 1915. » ee ee GENERAL INDEX TO VOLUME XXVIII Page Abbreviations, table of, on phylogeny of jaw CELE DISCCHSS (GIRS © CARRE fea lie re eat apie age 166 Sy LITERS OS ae ge oe a 142, 143 PRESSE LEARN 1 Sisy ec aik a hase iw eke bene 62-66 BEE AHETTSOT ON it la doo a tie Fie ees 67, 142, 143 PEE WHUMASCLES MN 5:0. ai. e Sav bisia ed ole cielo 68-69 hha Dae ae, ee 103, 133, 154 Adams, Leverett Allen, A Memoir on the Phylogeny of the Jaw Muscles in Recent and Fossil Vertebrates................ 51-166 WOME ATIEEG TC 28h PAI oe eis a ese ha tes ee 132, 133 Re WATKUSCIES IN! ./o.0 Shei sere eels oie 5 92-95 TESS, TEE BOSS 1) a ns eae ia lle Ree 69 MIELE IS is, Soe eis dda bos dot Cease 132 PPO MGIACIELS: < .605 2h 6 a bis aie ob ela wee yale 12 1 TST 077 Ta oe 199-200 SHUR ETEGIS OAS GA hea IEUE TENCE AERC OE pena 199 EPILENISUS Ce oe eee eat ees des He ee 199 PALL TTORILALS Ee he oe to chy leis aha eaten Cae 199. MIPILOTICENSIS. |. 25 ea Sa Se ees bes 199-200 POETIC AT HCL LIT \. 6 c5220. Ss valeie seas oO ep 29 Ambystoma, jaw muscles in............... 88 CEN BVTIEN ASN eRe ROE URE Reet DE REPL 192-194 PEIBOG UULOUE ote 2d oe icia ys oie Soa lass ee fs 193 SOATEST DS LE 2 ed Ng eR A ra ERROR 192, 193 IP PRDECIUISLEL Ay Pare a oy. ck eh ss SL Gl GG BE SGD 193 SRELITEGTEU cy thers bel chat a cakdad S. Ghe Sheehy Hb let 193-194 American Museum of Natural History; ref.. 61 MEER) cafes ... «sede 170 TUCRMMONGL... soa view bce ee 183-184 FG)... Sook cies ce See 184 WemMlANt 6. os. i eee 183 wightmanz#, 0. 8P............0000-- 181-183 i i 182 Embryology as criterion of homology...... 55-56 FEQUAGR Se. diwialei a. a Saya syaje's/s «seo Eee 110 BITYODS . soi 0 00s +0 om» 035, 0ne 83 reconstruction of Jaw muscles in... . 128-130 ES0DS:. 5 ov. ues alae 4 oo on 143 jaw muscles...) {... 2. oo eee 73-75 Ban opos@ur us. sas se sc ele 88 Euparkert@ oss... 6... om eh 132 capensis, fig........... Pre eee 3 132 Euprepes semiteniatus.................... 195 Evolution of jaw muscles in vertebrates and general summary of homologies..... 153-154 Extinct vertebrates, reconstructon of jaw muscles: im. 0... oss wae hoe 120-137 (See Reconstruction of jaw muscles in extinct vertebrates.) Felis, jaw muscles in.................22-- 118 bey fg? «. 5... seca: austen dyecetononensh keer eee 106 Fenestre of reptiles, relation of the jaw mus- cles to the temporal................. 154-155 Bick Rearefs: u.ckss..uiton ate Ree nu O4 Kield) preparation...........3.0 000. eee 35-36 Bijeld trips.) v0.6 os ss oot ee eee 21-35 Altoona... 5. crs. cake ee 29 Beacon Mountain................... 28 Boston .Bay.....%....¢.008 eee 30 Bronx Park...... Joe a DOR ee 24 Catskill... 0.2. .c e.es. 5. re 27 Catskill Mountains. ..:).. >. 0. eee 28 Delaware Water Gap............... 26, 28 Entire ar@ain. 5 6550+ 0s ane eee 32-35 Hackettgpown. ...).. <0: «oes eee 25, 28 Harrisburg. 4 <<... 35.0 ohh 29 Inwood .. 0%. dcccc09 60 ane ene 24 Lake George... ... 0.00.5 se see 29 Long Branch... s..0;... 03 26 Long Island); ..... 3.000%. doe 25 WMeriden.t )catenc) le omen see 27 New England: .\......... <<.) eee 31 Palishdesss .(.)0crhy sharon ee ee Sale aes Shawangunk Mountains... .. ......26, 28 Staten Island's. j.:22.sssetee 4 ee 23 Watchung; Ridges. ............ 0.205 eur 24 Fishes, tables of homologies............... 156 Forces, work of destructional, in New England and Middle Atlantic States...... 6-15 MlaACiErs. < 3.5.0 b\e fase os ce 12-14 StPEAMS, |..5 sins aloha. See aa 6-12 WEY OS so 'ci'an 8 ie, aylais so bb euen yee ene 14-15 : GENERAL INDEX TO VOLUME XXVIII 203 | Page Page Forms mountains, constructional.......... 16-21 INGFVE BID DLYy.5 hc ho esis re 56-59 | PO ee ae ee 2c Ee be Ee 17-18 Origin andinsertions) 66364) ss. hee ee 60 CUIHDIGK Ut ose esd Or ee. 19-20 Hamphrey,; Gh rete bs ca OP ORS 107 FNEECE Rc cals Soe Teta aoe 18-19 Hussakof, ues Tels. oe i. ss ke 61, 123, 126, 127 PLING =e EE eet ce eee ee eR 20-21 axl Gy. bbe eel sco kerk 5 Saws St ise ae 80 TL TET ee Stghod een eR es Be aoe tian Bd 16 PAOLA TI, CEOS te GUS Ag) eee | Agee gander Be 105 EDD an a ed ame ae I BA 16 PTOI EEre eT ee Ae ee Oe We ee 2 ee ee 59 Fowler; ref...... Ree era FL eee em 168, 189 DMMAMIT OIA See Ere Soon s veiedataes 57 LATTES Da ARI ER TORE! UR a ia Io AS Lk Sl 59 Function as criterion of homology......... 60-61 AV AETFUB ULES AE So. ihsscrarecks Sates 's © als 95-97 meroringery Mi ref.. 2... css ee! 59, 104, 138 EMC OOG MCLE BLIP). os i rare akc oi ciecileve ere cae oe 24 mutamura, 1H.> Tel. 2 ss es 104, 108, 147, 149 Jaw muscles in Recent and Fossil Verte- MEPAMPORE ET Ne one Siac ees a as ae OO 59 brates, A Memoir on the Phylogeny of the, EEN. RS eee et ai a 106 Leverett Allen Adams................ 51-166 Gallus, jaw muscles in.................. 99-101 Jaw muscles Sema, Wag BEL... oe 57, 114, 138, 150, 151 in recent vertebrates..:............. 62-120 EEE cs ees lore ceo wesasd aie sya's'S ae w Ss 106 Amphibia................-.-..00055 83-88 ) Gegenbaur, C.; ref.....................6- 108 AVES. oe eee eee eee eee 99-101 Geological map, radius 300 miles of New Whereis. 27 eae sy. tee alee tien 101-120 nt US ips peel i a ti ace ape aera 3 NAIBCER ree © tee ers eens ns eR adriana 62-83 Mt ae ee cs aie 93 Reptilia. .............. eee e eee 88-99 RIVE cree ao eee Sa cee ce cieaga ines 12-14 in vertebrates, general summary of CPST De oe Rage cis ae te peti Irae RR 12 homologies and evolution of...... 153-154 SE ESEN REV GEO HS Ls arte A IT a i aaa de 13 in vertebrates, homologies of....... 137-159 destructional forces.................. 12 phylogeny of, table of abbreviations... 166 Tg ITS Se eRe gr ee 14 reconstruction of, in extinct | = a aes Beha 11, 12, 13, 14, 27, 29, 50 WEDUCDEALES: 5:5. 01d a. 2 selec chee are 120-137 terminal WOrAINe. « - ic. <.s. ces.d-2 os oe a0 13 relations of, to the temporal fenestre of ee Oe a es 12 PODUMCR Seo oc co diciy oo cna ne ee anes 154-155 OF RE PEC (1 a Sa ie a eae 60 (1 ELAS HESS Ee ES SS ee Ba eR wit ia ial alae 93 Gero eee Aerie ee Seen. kien pe oe ee eee 55 Seoearicn, By; S.2 Tel... 2... ccs 56, 59, 81 ETI 9 Caco 1S) at a i SN Be a Dc 151 Gregory, W. K.; ref. Wostaneeky, 1. Von? Tele. 5. .-.< 6 fans ees 151 " 54, 61, 78, 83, 103, 120, 128, 133, 154 a segs am SE ie aera tens es Olle he ens 111 Labidosaurua, reconstruction of jaw muscles WUSCUs... 22-06 rere ee eee eee eens 111 “RAED ISIE Oe eae ce, SRR Ca 130-131 BeMMeACH: TEL. .,... - 5...» 0s ocecss cae 5 beget 172 Lake George, field trip.................-. 29 _ Gunther, A.; ref... 1.0.0... 5. eee eee te « Meaning = Sa 8/2 7 a Pn eae 120, 121 ; ERESETINCN oat Pa tFe oon eo Ss aie sin i ORS Vo 120-121 _ Hackettstown, field trip.......... reer Brig et PI IMD EEL A: Sve Soc lorsls tw Unierag Gh eee: ay 108 EUIIUGLUTUS., ete cee sews b ec neees 110 WE UTLOTI i a ic ae ors CER Ce ele Cas 198 { Harrisburg, field trip..................... 29 Me eo nee ae ee 198 Herpetology of Porto Rico, Contributions to PHBPIL NID, concoct oh ota Sire peieed tare ce eee 198 . the, Karl Patterson Schmidt......... 167-200 MO A, ce) he. oe foe 198 { UMD xo. Coa) ion vc Va Vola ThA shes «aa SWAT aa 108 Eejounes Misr rete: 2 ti hte 167 UN TINAI ico 5.508 ao) 5,2) ar oy v's rea, 5-6) A 102, 109, 140 TGCTOUMCUUINES 3. op .2 cists 5 okie ce) eee Wb ae ek 168-170 { BLN WHISCIBG INN 5 jes ans's, s Se, koe IS 119-120 TEED, ETS cee TR ee tao A area 168-170 - Homologies, general summary and evolution Lepidosteus, jaw muscles in............... 71-73 , of jaw muscles in vertebrates......... 153-154 PEPESVELER Sy CoN sheave REa lc COT, dig win. oS oS IR Ne 110 _ Homologies of jaw muscles in vertebrates . 137-159 RUPP ce he heey hgore aren Ade Gime) wots 106 ’ MATTER ERIAGG o/c k, ce an Ut peer 144-145 Literature, discussion of, on jaw muscles. . .52-54 RENN eA rei a ee hee ea 148-149 Lobeck, A. K., The Superb Position of New MMESIAVILSLIEGS 3 fsa 6s, arch a wb isa 149-152 York City as a Center for Physiographic LS ears ee eS ee 140-144 UME R CR Soe sites © Ra eee By Pa e See PRD an i ao ST 1-50 EREDAR EMG) pe iac,5 Sy oes Se br isk os Sw SHRI 146-418 aneohranoh Held trips: . s,s 6 xls miecarsyeyncel 26 Homologies, tables of.................. 156-159... Long Island, field trip... 5... 0. Ges esianewss 25 Meaney, Griteria Of... 6... ee Pek sen 55-61 LCE rt @01 [a ee RO get Sa 55-56 SM CMASPENI NER Go anv gens cles doc ae Base Waa 60-61 Lubosch, W.,; ref. 94, 95, 103, 138, 140, 144, 148, 152 RIE Ma hehe ey OR nhs IN Si tN 211 204 ANNALS OF THE NEW YORK ACADEMY OF SCIENCES Page PEA NTO RRS PAT Roe: Neha ROU Aa eet ane gnmnE Foe vena 194-195 UV EL G5 he 5. ao cco hj SER a ER 195 GVO LIVED sy Waele oo ou Scay Ses I ea 194-195 NA GCrOPUStA Acs ois Se Sa 107, 110 11 Oa Oe ae opr A mR De pant Ran pak key 106 Wheilllnuretic toe rayece: a acre eusaebas "enhe tok nner nee 55 Mammalia, homologies of jaw muscles in 149-152 jaw muscles in.................... 102-120 Did elphiysrris ssc teke siansrs Grohe sss are 115 I CLAS is ee ie eyecare pha ee: 118 FL OTLUOV SAL eee IE eis Doe RE 119-120 Mionotremes)..¢. 3.0... cq ae sas os 111-114 MUS pa RS 8 eet oo hs eae ake oto 117-118 SOLENOLOTUME: wise ec PRieua ree ae ees 116 tables of homologies......... He canoe 158 Mammals, tables of homologies............ 158 Miarioniy (Geis * Tks... os ccuneteinine ees 63, 64, 65 MicMiurrich, J. Pisirefii. 53.5524 s sm oe 69, 142 Mieerwarth 3 tef. oie cesses sa ie ee ane 184 Memoir, A, on the Phylogeny of the Jaw Muscles in Recent and Fossil Vertebrates, Leverett Allen Adams................ 51-166 Meriden, field trip... .:......00000 0000055 27 Monotremes, jaw muscles in............ 111-114 Morris) BiG; ref soee se ib taeiaa see ae 37 Mountains, as constructional forms........ 17-21 LOC IE. ee Reeon eae ce ee is 17-18 COMPIER ie.c) comin OR 19-20 gayi k ee etapa leet © aaahe Se 3, 5, 7, 18, 30 10} Co Caro NEM Re See iran iT era ari SS DPREOIS aah Fc DO 18-19 1 1a eR Ree a tg Fie De eae yn NS 20, 32 VOLCANIC ait tens eens icons ate tera om 20-21 2 OF f= be ERENCE REE REE ior CFT eas 21, 50 Mus, jaw muscles in................... 117-118 DT TIS CATAL SA, sre IPN GA SO are er Re ee Re 64 MGLOSLOTIA Sho sa a ee os elena tae ES 127 Neoceratodus forsteri, fig................... 81 Neoceratodus, jaw musclesin.............80-83 Nerve supply as criterion of homology..... 56-59 New England, field trip.................. 31 New York City as a Center for Physiographic Study, The Superb Position of, A. K. Lo- EC iste See hu Miceeene Seen ohne ese 1-50 New York City, geological map, showing radius of 300 miles..................... 3 Micholarus scsereties. soc. seco cit eee: 61 Origin and insertion as criteria of homology.. 60 Ornothorhynchus.......... 59, 107, 111, 112, 138 BeBe Peter eas tec chs iin Su, Sorel S Page 106 Osawa, Girreh pixie seiee eu ees 86, 91, 92 Osburn Re C@.s rel. see a eee ee 61 Osteolepist. 42. as ea eae eee 78, 130 Palinwrichthys....6 00) ae See ee 143 Jaw. TOUSCLES IN:.... 5 «c's ee eee ee 76-77 Palisades, field trip.................e000+ 23 Parsons, F. G.; ref........ 538, 104, 105, 107, 138 Patten, ‘W 3:rets ci)... acest are ee een 121, 123 Page PetromyZon 66 3245.) ok i eee 57 Phylogeny of jaw muscles: statement of problem................ 55 table of abbreviations................ 166 Phylogeny of the Jaw Muscles in Recent and Fossil Vertebrates, A Memoir on the, Leverett Allen Adams................ 51-166 Physiographic Study, The Superb Position of New York City as a Center for, A. K. Lo- beck... jcc. . eosin inden eee 1-50 Pipa americana: ..:... 06. + sons see eee 83 Pisces, homologies of jaw musclesin...... 140-144 jaw muscles in...................00. 62-83 Acanthias. 005 $s.0. 0) eae 62-66 Acipenser . oso d Ha eee 68-69 AMAD sos. s weiss ain ee 69-71 Anguilla «i005 oi Ok eee 75-76 Ceratodus:. 5.00... 0 se eee 80-83 Es0n. sso. P06 oe 73-75 Lepidosteus......... 32> et sae 71-73 Neoceratodus...........2000000- 80-83 Palinurichthys................0. 76-77 Polyodon..... os. a3 2e2 eee 66-68 Polypterus <0 056i. 6: Hoe 78-80 tables of homologies................. 156 Placodermi, reconstruction of jaw muscles BTS SS Serena Waiaie Borla ee 120-122, 123 Plains, coastal =; ..2.,..¢000. ve. ee 16 constructional forms................. 16 GiP8) 5 65. lek ek ene 16, 17 stages in development of............. 16 Plateaus, constructional forms............ 16 GG iso bids ee aiaea ve wee 17 Pollard; Hi. Bi3. ref:.. 2)... 0 ©. gee ee 78, 79, 80 Polyodon. coin Gina cie see 142, 143 jaw. muscles in... ...... 1.5 oes 66-68 Poly plernts® «2.2 so once oe eee 81, 130, 143, 147 jaw. muscles in... ...... PAARL ” ar 4 q & > La ad ~ ashen ear ttpenn 5 ~ ~.. ae & wry phArhe- uu mLaAsARArscs®, : yur 2 Wh é 2a » r ; yoy . 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