496 r»R. C. I. FORSYTH MAJOR ON 



I.eboucq's view that the human pisiform is the homologue oi^ the mammalian pisiform 

 minus the ossicle he figures in the Gibbon receives confirmation by a discovery of Pfitzner's 

 in the human adult carpus. He found in five cases a proximal process of the pisiform*. 

 To this " jiisiforme secundarmm " would correspond the " uhiare antebrachii " of Thilenius, 

 met with in ten manus of five embryos, where it is situated volad and ulnad of the proc. 

 styl. ulnai, and proximally from the pisiform f . Both German authors take this element 

 to belong to the same category as the os Camperii, viz. to be a carpal of a " preproximal 

 series." We have, however, seen that Leboucq shows that the os Daubentonii, which in 

 Hijlobutes is not unfrequently an independent ossicle, is contained in the mammalian 

 pisiform. For my part, I see no stringent reason to assign this os Daubentonii to a 

 "preproximal" series; from its position I consider it to be the first, proximal, carpale of 

 the fifth ray, and it might therefore appropriately be designated as V. 1 ; it corresponds to 

 the 1. 1 on the radial side, the radiale marginale, which in Echidna actually articulates with 

 the radius (Owen). In Eeptilia, especially in Emydidae, we frequently find an ossicle or 

 a cartilage occupying the position of a V. 1. Its absence in the Urodela is easily explained 

 by the reduction of the ulnar part of the urodele carpus, even the fifth digit being lost. 

 The reduction of the ulna and the ulnad extension of the ulnare may account for its 

 being, in Mammalia, generally situated on the volar face. 



What, then, is the distal part of the mammalian pisiform ? One might suggest, as the 

 easiest expedient for getting rid of this embarrassing element, that it is V. 2, viz. the 

 second car})al of the fifth ray. 



But, besides there being, as we shall see hereafter, another competitor for this distinction, 

 there is not the slightest evidence of the distal pisiform having at any time occupied a 

 similar position. On the other hand, it shows evidence of a former greater complexity. 

 In most, if not in all Mammalia, except Man and the Anthrojioids, the pisiform is 

 provided with a distal epiphysis; and in some there is more than that. In the Hodent 

 Bathyeryus mariUnms, as described by Von Bardeleben, "... the iJrsepollex and the 

 postminimus are both very well developed. The latter consists of two bones, of which 

 the proximal {pip.) is the true pisiform, and measures 5 millim. in length, while the 

 distal is 7'5 millim. in length. We must therefore in the future distinguish a proximal 

 from a distal 'pisiform,' and I regard the former as, in all probability, the carpal, and 

 the latter as the metacarpal segment of the postminimus " J. 



Two skeletons of Bathijergus maritimus are in the Natural History Museum, neitlier 

 of them quite adult. In the older one, which is the original of Voa Bardeleben's figure 3, 

 the distal part of the pisiform is incompletely ossified, as showm in the figure ; it is still 

 completely cartilaginous in the younger specimen. A similar, more or less ossified distal 



* Morph. Arb. iv. p. 508 (189-5). " Dieser Fortsatz war (in vier Fallen) proximal, utid zugk-it^h eher etwas 

 dorsal als volar gerichtet. .Seine plane Fliiche stellt eine coiitinuierliche Fortsetzung der Gelenkfliiclie des 

 Hauptstiicks dar ; im tjbrigeii war der Fortsatz riugsberum duroh eine tiefe Einziehung abgesetzt."' 



t Morph. Arb. v. p. 470 (189G). 



X " On the rroepollex and Pra;hallux, with observations on the Carpus of Thei-iocksmus phylarchus,'' Proc. Zool. 

 Soc. London, 1889, p. 260, pi. xxx. fig. 3, pi.p.^pi.d. ; id. Verb. Anat. Ges. 3te Vers. Berlin (Ergiinzungsheft) Anat. 

 Anz. iv. p. 108 (18S9). 



