18;)9.] ON THE OSTEOLOGY OF PHOKOraiACOS INFLATfS. 437 



between the radius and the ulna, and articukitingwitli tl e f(Tmer,. . . 

 its position was distad from the h'gament connect iiig ihe radius 

 and ulna, but proximad from the wrist fissure" (Handgvlenkspalte).' 

 To judge from the figure, this ossicle of the Plmscolomys is situated 

 slightly more proximad than in the Rodents and in Lepidolemiir. 



It is not for me to decide whether the ossicle of the Primates, 

 Rodents, and Phascolomys is really the homologue of the human 

 so-called intermedium antebrachii, uhich last in the embryo as well 

 as in the adult is situated more ulnad, and — when it does not 

 disappear by reduction — becomes fused with the proc. styloid, ulnse, 

 or secondarily imbedded in the meniscus." The alternative is, that 

 the "intermedium antebrachii" of man may be, after all, the same 

 element of human embryos which Thilenius has called ulnai'e ante- 

 brachii'', which corresponds to Pfitzner's pisiforme secundarium in 

 the adult ^, and is besides the homologue of the " ossiculum Dau- 

 bentonii'' of Hijlohatcs and Inims '. To judge from Leboucq's ^ and 

 Kohlbriigge's '^ figures and descriptions, the ossiculum Daubentonii 

 must be assigned to the carpus rather than to the antebrachium. 

 It seems to form, as a rule, the proximal portion of the pisiform 

 of Mammals, except in man '^, and I consider it therefore as a 

 marginal ulnare — the first, proximal, element of the fifth ray. 



Mr. C. W. Andrews read a paper on the osteology of one of the 

 great extinct birds of Patagonia, Phororhacos hvflatus. He described 

 in detail the structure of the skull and skeleton, and compared 

 them with various recent forms of birds. The evidence as to the 

 affinity of this type was somewhat conflicting, but on the whole 

 pointed to a relationship with, the Gruiformes, as had been pre- 

 viously suggested by the author. It seemed probable that the 

 aberrant Cariama was the nearest living representative of Plioro- 

 rhacos, being related to it somewhat in the same fashion as the 

 small modern Armadillos are to such great extinct forms as 

 Glyptodon and Panochthus. 



This paper will be published in full in the Society's ' Trans- 

 actions.' 



1 Morph. Arb. v. p. 10 (1895). 



2 Morph. Arb. v. p. 7 (1895). 



^ Met with in ten manus of five embryos, and situated palmad and ulnad 

 from the proc. styl. ulnss, and proximad from the pisiform. See Morph. Arb. 

 V. p. 470 (1896). 



* In five cases a proximal process of the pisiform was found. " Dieser 

 Fortsatz war (in vier Fallen) proximal, und zugleich eher etwas dorsal als velar, 

 gerichtet. Seine plane Flache stellt eine continuierliche Fortsetzung der 

 Gelenkfliiche des Hauptstiicks dar ; im Uebrigen war der Fortsatz ringsherum 

 durch eine tiefe Einziehung abgesetzt." Morph. Arb. iv. p. 508 (1895). 



5 Xohlbriigge, I. c. pp. 338, 339, pi. xvii. fig. 9 (1890-91). 

 ® Arch, de Biologic publ. par Van Beueden et van Bambeke, v. p. 83, pi. iv. 

 fig. 28. 

 ' L.c. 



* Leboucq, I. e. p. 83. 



Peoc. Zool. Soc— 1899, No. XXIX. 29 



