OCR Text |
Show 278 THE MARQUIS OF TWEEDDALE ON A N E W HORNBILL. [Feb. 19, the general colouring of the plumage there is little or no difference. It is the form of the casque that provides the differential specific character. Instead of being produced forward as in B. hydrocorax and B. mindanensis, with an abrupt, compressed, and elevated anterior margin, the superior plane of the casque loses itself and dies away on the culmen. The superior plane of the casque is not flat but arched along its length, the crown of the arch during the course of its anterior half forming an almost acute ridge. In the Fig. 1. Side view cf head of Buceros mindanensis. Head of Buceros mindanensis, from above. two known species the contour of the superior flat plane of the casque is that of an oval, the posterior end being rounded and the anterior pointed. In this Leyte species the posterior end is also rounded ; but the sides, instead of gradually expanding to the greatest breadth of the superficial area and then gradually contracting to the apical point, continue in almost parallel lines for about two thirds of the length of the major axis of the casque, and then terminate abruptly, forming corners from which the sides of the remainder of the casque recede until they reach the culmen. [S. Leyte, cS (adult), September. Iris light yellow ; orbital skin darkest sepia, almost black ; gular skin dark Indian-yellow; feet coral-red ; nails dark brown-grey.-Everett.'] |