1881.] ANATOMY OF THE JAfANAS. 641 



is a muscular gizzard, lined by a rather thick and hard epithelium. 

 The contents of the stomach, in one of the specimens examined, con- 

 sisted of small seeds mixed with vegetable debris and small frag- 

 ments of stone. The right liver-lobe is elongated, and twice as large 

 as the left ; and there is a well-developed gall-bladder. The caeca 

 are lateral in position, and closely approximated to the intestine, 

 which makes them difficvilt to see. They are mere nipples '2 inch 

 long '. In this respect Parra differs from all the Rallidse (except 

 Porzana notata) which have been examined, as in all of these the 

 caeca are long, sometimes very long. Of the Pluvialine birds, 

 only the Plataleidse and Rhinochetidse, with Sterna, Lams, and one 

 or two others, have such short cseca. The intestines measure, in 

 these two specimens of Parra jacana — small intestine 12'3 and 

 13" 2 inches, large intestine Tl and 1"0 inch respectively. 



In Parra jacana and in Hydrophasianus africanus, as also in 

 Metopidius africanus, as already recorded by Garrod ^ there are 

 two carotid arteries. This is the number found in all the Rallidas, 

 and in most of the Pluviales, excepting the Turnicidse and Arctica 

 alle, according to Garrod ^ where there is only the left developed. 



Myoloffy. 



Parra jacana resembles P. (Metopidius) africana, as recorded by 

 Garrod *, in possessing the ambieus, femoro-caudal, accessory femoro- 

 caudal, semitendinosus, and accessory semitendinosus muscles, all 

 well developed *. Their formula is therefore AB . XY ". In both 

 these species the gluteus primus is well developed, covering the 

 biceps superficially towards the median line ; the gluteus quintus is 

 also well developed. As in the Rallidse, and the Gruidae^ and Eury- 

 pyga, amongst the Pluviales, the area of origin of the obturator 

 internus is triangular, as it is also in Sydrophasiatius ; in the Plu- 

 vialine birds generally it is oval. The two deep flexor tendons of 

 the foot are not at all ossified, but completely blend together some 

 way up the leg — in Metopidius, in fact, just below the joint. There 

 is no slip at all to the hallux, as was also found to be the case in 

 Parra a/ricana" and Hydrophasianus by Prof. Garrod. This is the 

 more remarkable on account of the very large size of the hallux in all 

 these birds. A special tendinous slip to that digit is very frequently 

 present in birds which have a very insignificant hallux indeed ; and I 

 know of no other case of a bird with such a large hallux as that of 

 the Parridse lacking the tendon. This fact would seem to indi- 

 cate that the Parridse may have been developed from some form 

 with a more normal-sized foot and a small hallux, which had no 



' In Hydrophasianus chirurgus there is a strong gizzard, and the left liver- 

 lobe is smaller than the right ; the ciEca measure 'IS inch, the whole length of 

 the intestines being 12 inches. — Garrod's MSS. 



2 P. Z. S. 1873, p. 469. » l. c. pp. 469, 470. 



* P. Z. S. 1873, p. 641. 



6 In HydrophaHianus all these live muscles are also present. 



6 Cf. Garrod, P. Z. S. 1874, p. 123. 



7 Garrod, P. Z. S. 1876, p. 199. ' P. Z. S. 1875, p. 348. 



