WIELAND : THE OSTEOLOGY OF PROTOSTEGA 283 
ulnare, radiale, and pisiform, with fragmentary phalanges, and many broken pieces 
of the plastron. The 7 sitw portion consists of the right anterior part of the skele- 
ton, and was secured on a single slab of the chalk matrix, in which it still remains 
intact, as shown in the accompanying drawing, Fig. 1, by Mr. Prentice. It includes 
the following : the lower jaw in oblique inferior view, with the two larger hyoidal 
elements ; the skull in superior view, less the left squamosal and with the right quad- 
rate disarticulated and its anterior surface up; the right humerus, radius, ulna, wrist, 
and palmar elements in superior view, and all in place, except the radiale which 
has slipped across to the posterior border of the wrist ; the right ala of the T-shaped 
nuchal with the first and second marginals, and the distal half of the second rib, all 
in place and resting over the proximal extremity of the humerus. 
Although the various bones are more or less crushed, after the manner of most 
fossils from the Kansas chalk, the contours are exceedingly good. In the skull, as 
simply crushed down in the vertical direction with little distortion of parts, there 
appear in clear preservation and united by distinct sutures the premaxillaries, 
maxillaries, prefrontals, frontals, postorbitals, and parietals, with the right squa- 
mosal, jugal, and quadrato-jugal. The cervicals have in some way been dissociated, 
but the skull les in a normal position with respect to the anterior border of the 
carapace, from under which the right fore-flipper projects in the normal position, 
the hand being bent back pronately over the position of the third marginal, part of 
which appears in view. 
It will at once be seen what exceedingly satisfactory information is furnished by 
the present specimen, as compared with all other examples of Protostega hitherto 
found. ‘The more important measurements afforded are the following : 
em. 
HO wennave-e bxtreme)leng thyoteramuss:-seerernnedoessesrcsienccnccreececsrs stern cere iee se omer 37 
Extreme length of median symphySis..............2...cseecee:secesseeeeeceeeeeeeerseeees es 16 
Cranium: Extreme length (as crushed flat) measured from end of beak to posterior ex- 
NIN? Oi CLONAL OES Rnosaccossoccceccosone caekBe gAcES sconbUeoeDdceR obdocaadHaecaRooRC 58 
Medianglengthyofimanialiopeningiec.sscesc-ee-nere=c sen edee carte ceestatseeenelienses eres 7.5 
Greatest width of narial opening..............-...0..jcceeceeeeeereseeseeeeeecsceeeeesasee: 5.5 
Orbital border of the prefrontal 
Antero-posterior length of orbit 
Humerus}: Tzenpth ‘across head) :..<.scc5 ee scivesevsecncesssseerceet seccenactesoesee oy seesena cde sceusmees ss 
Wadth of distalend i ct. f2 sates seus ccresis so naivesseaneesese 
RAC TUS Hs PILEN PED eos c.sseccscs vc cevandeaervesdcatecoectesecseeaecn sce enatenere rn censrocne 
Ulna: Length 
Carpalia : Width across the five carpalia in place...............0--02cesceerereaneesecneeeseneeseesers 18 
Metacarpalia : (Length of 1-5 resp.) ; 7( + or — ), 10.5, 12, 12.5, 10 ( + or —) em. 
The above cranial and hand measurements have not hitherto been obtained in 
Protostega, whence it is of interest to note, that, allowance being made for the crush- 
