714 RHYNCHOPIN^, SKIMMERS. 



The cousolidatioQ is perfect for fully two-tbirds of the length of the hill, causiug the 

 nasal apertnre formed by the divergence of these processes to be extremely small, 

 short, and' narrow. The mandibular processes are also closely approximated to each 

 other (only a narrow groove being left between them) for two-thirds their length, 

 when they rather suddenly divaricate at a considerable angle. The palatal fissure thus 

 left between them is very short, and only commences about opposite the termination 

 of the palate bones, instead of much further forward, as in the other subfamilies. The 

 su])erior or mesial process of the intermaxillary is thus almost wholly concerned in the 

 production of the shape of the upper mandible. It is large at the base, being there as 

 broad as the os frontis, and about half as high as broad, with inflated, very convex and 

 bulging sides. Beyond the nostrils it becomes more compressed and deeper, and begins 

 to present a ridge along its culmen in place of the groove which exists at its base. The 

 sides become, as they advance, more and more compressed, and less bulging and convex, 

 until they terminate in a very acute point. This bone is remarkable in being holloiv 

 throughout, from base to extreme apex, with very thin walls, and consequently very 

 light. Its interior is partially occupied by a very light, delicate web of open cancel- 

 lated structure, most marked toward the base; more anteriorly its complete hoUow- 

 uess is only interrupted by delicate trabeculae of bone, which extend across, from side 

 to side, in every direction. This j)eculiarity of structure calls to mind the bill of the 

 Bliampltastidw. 



The bony frarae-work of the under mandible, though not abnormal in structure, has 

 yet even a more peculiar shape than that of the upper. The rami of the inferior max- 

 illa are at first nearly parallel, and are very thin and delicate. Toward their 

 symphysis they become stouter, aud very suddenly converge toward each other with 

 a considerable degree of convexity. At the symj)hysis, which is strong aud firm, 

 the tomial as well as the dorsal edges of the bone at once unite ; and the rami, thus 

 completely consolidated, extend forward as a straight, thin, sharj) iirolongation of 

 bone, with flat, erect sides, and perfectly straight edges, which converge toward an 

 acute apex. The axis of the symphysis declines downward at a considerable angle of 

 divergence from the axis of the rami. The conjoined tomia are at their base on a level 

 with the superior edges of the rami, but the dorsal outline is at its beginning much 

 below the level of the inferior edge of the rami, in consequence of a marked deepening 

 of the bone just at its symphysis. On account of the peculiar direction of the inferior 

 maxilla, the tomial edges of the two mandibles are not usually in contact throughout 

 in their ordinary positions. Posteriorly the upper outline of the rami dips down with 

 a, considerable angle to the articulating surface. This latter diifers from the ordinary 

 type in its width, which is great, in consequence of the development of its internal 

 aud external angular processes, aud in the depth of the internal concavity. These 

 differences correspond to the difl'erences in shape of the face of the tympanic bone ; 

 in the prominence of its malar and pterygoid processes, aud the depth of the sulcus 

 between them. The roughened ridges aud eminences about the joint for muscular at- 

 tachment are all well marked. The triangular space just posterior to the articulation, 

 for the attachment of the digastricus, does not present so much downward and for- 

 ward as in the other subfamiles. 



The single known genus of this subfamily is represented in North America by its 

 type species, the long and well-known i?. nigra. 



Genus RHYNCHOPS, Lifin. 



Phalacrocorax, Moehr., Gen. Av. 1752. 



Eynchops, Linn., Syst. Nat. i, 17.58 ; 1766, 228 {B. nigra), 



Enochopmlia, Briss., Orn. vi, 1860, 223. 



liliynchops, Lath., Ind. Orn. ii, 1790, 802. 



Animrhamphus. DuM. (Gray). 



Psalidorhampkus, Eanz, 182:5 (Gray). 



Jihyncliopsalia, Gloger, 1842 (Gray). 



The characters of the single genus being the same as those of the subfamily, it is 

 unnecessary to repeat them. 



Moehriug's name unquestionably belongs here, but is used in a different accejjtation. 

 Byncliopa of Linnaeus, more correctly written Bliynchops, may be employed instead, 

 though I hardly know upon what groimds, for as Liniueus called the Cormorants Pelc- 

 canus, Phalacrocorax, Moehr., does not conflict with a Liniuean name, and we date some 

 accepted genera back to 17.35. The original Bygclwpsalia of Brissou is variously 

 spelled by subsequent authors. I quote Anisorhamphus and Psalidorhamphus on Gray's 

 authority, having no means of verifying or completing the references. 



