OCR Text |
Show 314 DR. H. G A D O W ON T H E INTESTINAL [May2l, point out in a few words what are the points which connect them with each other; but still, in spite of many important diversities, there is something in the organization of the whole of their alimentary system which tells the experienced eye that the majority of them are allied together, and differ from the rest of the birds. However, this sounds vague, and is not an exact mode of discussing the affinities of the birds in question. The lowest Coracornithes are the Coccyges; this name is intended to comprise the Cuculidae and the Musophagidae. The Guculidce possess four intestinal loops, of which the second and first are right-handed. The loops are on the whole orthoccelous, but the apices of the two middle ones are often turned up, or the second loop is plagiocoelous. Moreover, they possess fully-developed caeca. In all these respects they resemble to a great extent the Gallinae; and this hint is considerably strengthened by Opisthocomus, which is, barring special features, exactly intermediate between the Cuculidae and the Gallinae. This is a conclusion which Huxley, Fuerbringer, and others have arrived at on independent grounds. The Musophagidce (Corythaix only examined) possess but three loops, of which only the first is right-handed. So far as the other two are concerned, they are isocoelous birds, and agree in this point with the bulk of the Coracornithes. The decreased number of loops of Corythaix is the result of tbe shortening of the gut, a feature always connected with frugivorous habits. I consider that the second loop of the Cuculidae has been suppressed in the Musophagidae, and that consequently their last two loops correspond with the third and fourth of the Cuculidae. The isoccelous feature of the Musophagidae is therefore reduced to a secondarily acquired one, and to a case of convergence towards the typically isocoelous birds. The Coccyges are therefore, like Opisthocomus, birds which have sprung from the Gallinaceous stock, and have followed lines of development which are directed towards the Coracornithes, and which in the Musophagidae have attained their highest features. The Picidae, Capitonidee, and Rhamphastidce are very close allies, and form the Pici. They differ, like the Epopes (Bucerotidae and Upupidae) from all the other Coracornithes in the alternating position of their four loops, which, in the frugivorous Khamphastidae, and in the likewise extremely short-gutted genus Upupa, are reduced to three by the suppression of the original second loop. Xantholeema, one of the Capitonidae, has this second loop still indicated. The total absence of caeca in all these birds is a coincidence, whilst there are no obvious characters, besides the anticcelous convolutions, which point to a close relationship between the Pici and the Epopes. There remains the large congregation which is, in the diagram, included in the isocoelous circle. Of these the Coraciidee stand nearest to the hypothetical ancestral or central stock, because they are the most generalized set, from which all the others can be derived. In one direction started from or out of the Coraciidae the Alcedinidee, which have reached a truly mesogyrous formation. Their lengthened gut, in conformity with their partly piscivorous habits, forms a left- |