374 BRITISH FOSSIL REPTILES. 



disturbed. The metatarsus (PI. 4-3, ii, iii, iv) was extracted in one piece ; the phalanges 

 of an outer toe (ib., i iv_5 iv) were extracted in a second piece : they had been some- 

 what distorted at the time of imbedding, for the matrix had hardened around, and 

 preserved them in that state. The phalanges of the toe of the opposite side of the 

 foot (ib., 1 II— 3 ii) were extracted similarly cemented together by the matrix, but in 

 their natural juxtaposition. Three of the phalanges of the middle toe (ib., i m— 3 m) 

 were also joined together by the matrix ; the fourth, or ungual phalanx of this toe, 

 was extracted separately ; but Mr. Beckles's attention having been, unluckily, diverted 

 to another subject at this time, the fossil got into the hands of an idle looker-on, who 

 cast it into the sea. All the other bones of the foot Mr. Heckles caused to be carefully 

 packed, and transmitted to me for description. 



I employed a skilful lapidary to clear away the adherent matrix, and to separate 

 the cemented phalanges of the distorted toe, for the examination of their articular 

 surfaces, and the result of my comparisons were communicated briefly to the Geological 

 Society of London, on the occasion of exhibiting the specimen at the meeting held 

 June 17th, 1857. 



As has already been stated, the bones, whether carpal or tarsal, which unite the 

 foot proper to the limb, are wanting. The metapodium,* fortunately, yields the 

 required proof of the precise number of toes. 



As a general rule, only the metapodials which bound or form the outer and the 

 inner sides of that segment of the foot have the proximo-lateral articular surface con- 

 fined to one side of the bone ; the intermediate metapodials show such surface on both 

 sides, for articulation with the contiguous metapodials. The metapodial (Pis. 43 

 and 44, iv), which will presently be shown to be the outermost, had its outer side 

 rounded, and simply roughened for the implantation of ligamentous fibres ; the meta- 

 podial on the opposite side (ib., n) also presented a convexity toward that border of 

 the foot ; but a small part of the middle of that convexity is articulated with a slender 

 rudiment of a metapodial (ib., i), which forms the real boundary of that — the inner 

 side of the foot. The upper portion of this metapodial, which resembles the " sphnt- 

 bone" in the metapodium of the horse, has been fractured and partially dislocated before 

 the induration of the matrix ; the lower portion of the bone is in its natural position, 

 and seems to have been anchylosed with the contiguous fully developed metapodium : 

 the extremity of this lower portion, however, is broken away ; so that, whether it 

 ended in a point, like the rudimental metapodials in the horse, or supported a 

 diminutive toe, like the metapodials of the spurious hoofs in the ox and musk-deer, 

 cannot be at present determined. 



* I use this word to signify the same segment in both fore- aud hind-limbs : " metacarpus " is the 

 specific term for the segment in the fore-limb; "metatarsus" for that in the hind-limb. But, in the 

 gradual reconstruction of the skeleton of a strange reptile, it is requisite to have a term expressive of the 

 more general kiiul of knowledge at first acquired. Metapodial is equivalent to metacarpal or metatarsal. 



