LAXD-TOETOISES AND AN EXTINCT LIZARD FROM MAURITIUS. 323 



DiDOSAURUS MAURiTiAxus. (Plate XLIV. figs. 1-16.) 



A short fragment, with three teeth, of the maxilla, five fragments of the mandible, 

 seven more or less perfect femora, and portions of three humeri have been described 

 and figured (with the exception of the maxillary fragment) by Dr. Giinther in the 

 ' Journal of the Linnean Society,' Zoology, vol. xiil. (1878) pp. 322-324. All these 

 bones had been collected in the Mare aux Songes. 



Mr. Sauzier has obtained many more specimens in the same locality : — 4 complete 

 left mandibles ; 4 complete right mandibles ; 10 right and 9 left mandibular dentals : 

 14 right and 14 left proximal halves of mandibles ; 3 complete frontals, of two large 

 specimens and one small ; 3 bases cranii ; 1 atlas vertebra ; 3 thoracic vertebrae, two of 

 which are successive and belong to one individual ; 4 lumbal vertebrae of a smaller spe- 

 cimen ; 1 lumbal rib ; 1 sacrum ; 2 fused vertebrae ; 4 post-sacral vertebrae (first, second, 

 third ?, and fourth ?) ; 4 right humeri ; 4 left humeri ; 4 ulnae ; 3 right femora ; 7 left 

 femora ; and 3 left ossa innominata or pelvic halves, one of which indicates a small 

 specimen. 



The largest of the complete underjaws measures 76 mm. in length. 



As was to be expected, the number of teeth is variable, namely 22, 23, 24, 24, 25 

 in the five most complete left dentals, and 20, 22, 23, 26 in the right dentals. 



The shape and proportions of the underjaws, of the frontal bone, and of the basis 

 cranii indicate that in the shape of the skull Didosaurus resembled the genus Cydodus. 



The largest humerus measures 42 mm. in length, the smallest 35 mm. ; all the 

 specimens possess a distinct entepicondylar foramen. 



The ulnae vary from 30'5 to 32 mm. in length. 



The largest femur measures 49 mm., the shortest 43 mm. 



P.S. — Since this paper was read, Mr. Sauzier lias published a memoir, which contains not only numerous 

 historical accounts, but also several excellent woodcuts, representing side and back views of the large Tortoise 

 living at St. Louis. It is entitled ' Les Tortues de terre gigantesques des Mascareignes et de certaines autres 

 iles de la mer des Indcs.' 8to. Paris, 1893. 32 pp. 



EXPLANATION OF THE PLATES. 

 PLATE XLII. 



Fig. 1. Type of Testudo sauzieri. Carapace No. 1. 



Fig. 2. Carapace No. I. ; posterior view. 



Fig. 3. Longitudinal vertical section through type-specimen of T. sauzieri. 



Fig. 4. T. sauzieri ; ventral view. 



Fig. 5. Plastron A. 



Fig. 6. Plastron F. Dorsal view, posterior portion, T. sumeirei. 



Fig. 7. Plastron F. Profile section through posterior portion. 



Fig. 8. Plastron F. Ventral view, posterior portion, T. sumeirei. 



Fig. 9. Carapace No. V. Probably T. i7idica of Perrault. 



