216 A. GUNTHEE ON SOME RARE REPTILES 



If we are allowed to make a conjecture as to the principal food of the Matamata, we 

 should be inclined to find it in small fishes, and especially tadpoles. These may be 

 allured to the animal by the waving fringes of its neck and head, and could be 

 readily seized in its feeble jaws, which would be equally ill adapted for cutting off 

 l)lants or for holding a larger and stronger prey. 



Although no good figure of the Matamata has been published, the descriptions are 

 suificiently detailed to render another description unnecessary. However, there are 

 two points which deserve special notice. 



Strauch (Chelonolog. Stud. p. 172) has already stated that authors give different 

 accounts of the extent of the gular plate. In fact, in some specimens the gular plate 

 is short, triangular, and bordered entirely by the postgulars, which form a broad suture 

 together. In other specimens the gular plate is oblong, elongate, reaching the pec- 

 torals, and entirely separating the postgulars. This lesser or greater development does 

 not depend on age, as both forms of the gular are found in very young specimens 

 preserved in spirits in the British Museum. Unfortunately the origin of the majority 

 of the specimens which I have had the opportunity of observing is unknown ; but 

 such scanty information as I have been able to collect would have led me to the 

 conclusion that the form with the short gular is peculiar to Guiana, and the other 

 form indigenous in the system of the Amazons. In that case the name of Chelys 

 fimbriata would have to be restricted to the former, and that of Chelys matamata to 

 the Amazonian race, so named and figured by Spix. However, the two specimens 

 living at the present moment (November 1880) in the Society's Gardens, which were 

 acquired at the same time and from the same source, show both modifications, and 

 therefore make me hesitate to see in this remarkable difference more than individual 

 variation. Its explanation as a secondary sexual character would be difiicult to 

 understand, and open to objection'. 



The second point to which I would draw attention is the coloration of the young. 

 The shell and soft parts of the adult are almost entirely of a uniform brownish-red 

 colour, resembling that of river-sand. Only on the neck faint outlines mark the 

 position of the spots which are so conspicuous in the young. Specimens preserved 

 dry become darker, brownish-black. The ground-colour of a young individual, the 

 shell of which is 3 inches long, is light reddish, as in the adult, but the areola of each 

 costal scute bears a large black spot; a brown line commences on the occiput, and is 

 continued along the vertebral line to the caudal scute ; two brown raised ridges diverge 

 from the frontal region towards each side of the occiput. The lower part of the pro- 

 jecting snout is deep brown. The throat is ornamented with four broad brown longi- 

 tudinal bars, the two middle occupy the lower side of the throat, and are confluent 

 near the chin, the outer are broader, and run from the angle of the mouth over the 



' Since these lines were written, the Zoological Society received two other examples, in one of which the 

 development of the gular plate is intermediate between the extreme forms described. 



