1899.] THE CAEPCS OF CTENOMYS. 431 



to its having been fused (" assimiliert ") with the terminal phalange. 

 The condition described in Ctenomys etc., while supporting the 

 first parb of Pfitzner's contention, seems however to point out, that 

 in part at least of the Mammalia the disappearance of the second 

 phalange has been brought about by elimination and not by 

 " assimilation." 



In the pes of the Insectivore Chri/^ochloris, the phalanges of all 

 the five toes are reduced to two, and all the five toes show a dorsal 

 ossicle riding on the interphalangeal articulation. This coincidence 

 would seem to be significant ; but I have at once to state, that 

 in the manus of Oryzoryctes tetradactylus, which has the normal 

 number of three phalanges in the four digits present, I have found 

 the ossicle in question on the distal interphalangeal articulation of 

 the second digit, and do not doubt that it was present on the 

 others also. 



The only recorded dorsal ossicles of Man occur on the metacarpo- 

 phalangeal articulation of the thumb, and are noticed by Kulmus ' ; 

 one case also having been found by Pfitzner ^ ; in the same place, on 

 the great toe an ossicle is recorded by Kulmus ^. In the Canidae, 

 dorsal ossicles are limited to the metacarpo- and metatarso-pha- 

 langeal articulations *. The dorsal ossicles of the manus of Talpa 

 europcea have been figured repeatedly (Blainville, Owen, Flovt'er, 

 &c.), but nowhere do I find a reference made to them in the de- 

 scription of the skeleton, which almost seems to show that they 

 have not been recognized as free ossicles, but considered to be 

 processes of the phalanges. In this Insectivore the three middle 

 fingers of the manus have each two dorsal ossicles, one on the 

 metacarpo-phalangeal articulation, and one on the proximal inter- 

 phalangeal. In the first and fifth digits only the latter articulation 

 shows an ossicle. In the pes I find them only on the proximal 

 interphalangeal articulations of all five toes. In a skeleton of 

 Condylura, the dorsal ossicles seem to have been partly cut away, 

 so that I cannot make a definite statement. It is noteworthy 

 that, on the proximal interphalangeal articulation of the fifth digit 

 and on the homonymous articulation of the fourth toe, two ossicles 

 are present. In a mounted skeleton of Myogale moschata in the 

 Natural History Museum, I find dorsal ossicles on the proximal 

 interphalangeal articulations of the second, third, fourth, and fifth 

 digits (on the latter there are two ossicles). In the pes, the articu- 

 lator has almost thoroughly done his "duty," for there is only 

 one dorsal ossicle present, viz., on the proximal interphalangeal 

 articulation of the third toe. In Oryzoryctes tetradactylus, dorsal 

 ossicles, in addition to the above-mentioned, occur also on the 

 second, third, and fourth proximal interphalangeal articulatious of 

 the manus, as well as on the same articulation of the fifth toe, and 

 may have been cleaned away in the other proximal interphalangeal, 



^ Kulmus. ' Tahulce anatomicfe,' p. 62 C1732) ; id., Miscellanea Med. Phys. ii. 

 p. 328 (1720). Quoted from Pfitzner, Morpb. Arb. i. pp. 604, 742 (1892) 

 ■^ Morph. Arb. i. pp. 604, 685 (1892). 

 ^ L. c; of. Pfitzner, l. c. p. 742. 

 " See Pfitzner, Morph. Arb. i. p. 603 (1892). 



