The Keltic type is the second oldest in Ireland 3.36 years above the mean age. The type is 0.60 pounds below mean Irish weight, but does not deviate significantly from average stature. The thoracic index in this type is significantly high, because the chest is deep relative to its width. It is exceeded in this index only by the small Pure Mediterranean group. Head circumference is markedly low since head breadth is meager and head length, although large, fall below the of the numerically strong Nordic Mediterranean type. The cephalic index 76.59 is the minimum for Irish types. Head height is lower than that of any other type save only the Pure Mediterranean. The length-height index is next to the Irish minimum, while the breadth-height index is significantly high although exceeded by two Nordic types and the Nordic Mediterranean type. The forehead is very narrow and the front-parietal index high. The bizygomatic diameter is depressed, but significantly higher that the average values found in the Nordic types. The cephalo-facial index is higher that that of any other type save only the Nordic Mediterranean. The bigonial diameter is somewhat low and the front-gonial index is highest for Ireland. The gonial index is moderately elevated. The high facial index 91,1 is exceeded only by that of the Predominantly Nordic type. The upper face is particularly long. The upper facial index average demonstrates that this type has relatively the longest and narrowest upper face. Noses are a trifle long, probably in part an effect of advanced mean age and also they are a trifle broader that average. Thus the nasal index is also a little above average.
The Keltic type is very light-skinned, although exceeded in this respect by the three blond types. It falls below these types only in pronounced vascularity. The type is relatively low in freckling and also has fewer moles. All kinds of hair form occur, with low waves in the modal position. However, the Keltics present the strongest assemblage of straight-haired individuals to be found in any Irish type, save the Pure Nordic. Baldness and graying of head and beard are excessive in this type doubtless because of the high average age. The modal hair color (46.9%) is flat brown, but a strong minority (39.7%) has dark brown hair, and red-haired contingent amounts to 5.7%. In darkness of hair pigmentation, this type is exceeded only by the small group of Pure Mediterranean’s and by the large Nordic Mediterranean group.
All Keltics have pure blue or gray-blue eyes. Almost 54 per cent of Irish blue eyes belong to members of this Keltic type, although the type constitutes only 25.3% of the Irish type series. Irises with scalloped patterns reach their Irish maximum and clear irises are greatly in excess. External eye folds are slightly more that ordinarily common in this type. Upward slant of the eyes slits is more frequent in the Keltic type than in any other except the Pure Mediterranean. Variations from medium height of eye openings, when they occur at all, are low more that is ordinarily common, but these are not characteristics. This type has a higher percentage of persons with pronounced brow ridges that any other Irish morphological type. Foreheads incline toward the more sloping forms. Nasal depressions tend to be deep; straight nasal profiles slightly exceeded the convex form. Membranous lips are rather more than ordinarily thin. Teeth loss, wear, face shortening by tooth wear, and caries are at the maxima in these Keltics, but, reasonably, this condition must be attributed to the high mean age of the type. The Keltic type is average in frontal projection of the molars and is high in medium lateral projection. Gonial angles are infrequently prominent. Hollowness of the temporal region is a distinct feature as is also marked occipital protrusion. Although lambdoid flatting occurs in nearly three-fourths of the Keltics, this feature is less common in the Keltic morphological type that in any other. Occipital flattening is relatively infrequent.