INTESTINAL TEACT OF BIEDS. 259 



so-called intestinal nerve is unusually large and visible, and it was in members of these 

 families that I first noticed it. In the majority of cases, however, it is not readily seen ; 

 moreover, much of my material consisted of rather badly preserved spirit-specimens, or 

 of birds that had died of disease in which tubercular and fatty degenerations of the 

 mesentery were a conspicuous feature, and I am able only to give a few almost casual 

 notes, which, however, may serve the purpose of redirecting the attention of anatomists 

 to a very peculiar and interesting set of structures. A good deal is known about the 

 paired ganglionated mesenteric chain (G-renzstrang of the German writers), thanks to 

 the observations of many writers, of whom the chief are Wiedersheim, Gadow, Gaskell, 

 and Marage. In the cervical region [Wiedersheim (36. p. 350), Gadow (12. p. 394), 

 and Marage (23, passim)'] it divides into a deep and a more superficial portion, and irregular 

 traces of this division persist in different birds in the posterior parts of the body. In all 

 cases it appears to have more autonomy ; that is to say, to be in less intimate connection 

 with the metameric spinal nerves than in most other vertebrate forms. In the lumbar 

 region there arises from this a very complex plexus with large ganglia on the edge of the 

 stomach, on the ovary, on the supra-renal capsule, and further back near the rectum. It 

 is from these ganglia that the so-called intestinal nerve of birds arises. Concerning this 

 peculiar nerve the literature is very scanty. Remak (32, 33) appears to have called 

 attention to it first, but most later writers pass it over almost completely Thus Gadow, 

 Wiedersheim, Furbringer, and Beddard, in their ornithological and anatomical treatises, 

 pass it by. Oppel, in his great work on the anatomical tract (30), is content with 

 discussion of the plexuses actually in the wall of the gut. Gegenbaur (14), in the most 

 recent edition of his ' Text-book,' mentions the existence of such a nerve in reptiles, and 

 states that it is best developed in birds ("Am meisten sind diese Nerven bei Vogeln 

 entwickelt. Ein den Mitteldarm begleitender Nerveustamm geht am Enddarme in 

 mehrere ansehnliche Ganglien "), and adds that it is undeveloped in mammals. Marage 

 (23) has given the best account of it, and states that it differs in its arrangement in 

 different birds ; but his figures are rather difficult to follow, and he is incorrect in stating 

 that it does not occur in rapacious birds, and he seems to have overlooked it in the 

 Ratites. As I have already stated, I do not pretend to have made anything that 

 approaches to a complete study of it, and the figures that I have been able to give must 

 be taken only as rough anatomical notes. Special study by special methods on material 

 in good condition is required *. I can say, however, that in every case since I was 

 aware of its existence, where the material was in sufficiently good condition, I found it 

 present, and I do not doubt that this presence is invariable. It arises usually from two 

 or three main nerves, which leave the ganglia corresponding to the solar plexus and the 

 ganglia over the ovary and supra-renal capsule, and enter the mesenteric expanse which 

 is the support of Meckel's tract. These, or some of these, are represented in figures 1 

 and 45, and I have worked them out in several unfigured cases. In fig. 72 there is a 



* Since writing this memoir, my attention has been directed to a beautiful memoir by The'bault (34), which 

 contains, inter alia, an elaborate study of the modes of origin of the intestinal nerve in various types of birds. 

 P. C. M. 



