REVISION' OF MALACLEMMYS, A GENUS OF TURTLES. 19 



All the terrapin of this species that I have seen alive came from Rockport, Texas, but the) are 



said i 'cur southward as far as Brownsville, at least, and northward as far as Galveston. In the 



American Museum of Natural History there are four specimens of this turtle, Nos. 801, 802, 804, and 

 805, which were probaljly collected by Maximilian; no locality is given for them other than Texas. 

 It is quite possible that the range of this species and that of M. pileata merge somevi here between i fal- 

 veston and New Orleans, and it may be that the two will be shown to be more closely akin than is 

 indicated by the classification adopted here. The very dark brown individuals of M. littoralis are very 

 similar in general appearance to the .Mobile Bay specimens of M. pileata, but may usually be distin- 

 guished by the higher and heavier body and the white upper lip. 



A very interesting malformation, consisting in the longitudinal division of one or more of the 



vertebral plates, was observed m many individuals of this species, a condition s immon that it was 



really difficult to pick out a full-grown specimen which did not show it in some degree. As to the 

 possession of the inguinal plate, these terrapin were variable; of 5(1 specimens examined for this 

 character, 2t> had it and in 24 it was wanting. 



The young of .1/. littoralis are very remarkable, and in the absence of any other distinctive chat ac- 

 tors would serve to separate the species from W. centrata. I have secured agood series of the young 

 from eggs laid in one of the terrapin pounds near Crisfield, Maryland. They are much larger than 

 the young of }f. centrata, having probably twice the bulk, and seem much more vigorous and lively. 

 Thi' first vertebral plate is raised on the middle line to form a broad, low carina; on tin- second plate 

 the elevation is greater, and stands out as a smooth boss on the otherwise finely wrinkled plate; the 

 elevation on the third plate has the form of a hemispherical button with a well-marked constriction 

 around the posterior half of the base, so that it stands up prominently above the plate posteriorly but 

 anteriorly slopes into it; on the fourth plate the elevation rises into a knob-like protuberance from a 

 base which is constricted all around; the tubercle of the third plate is usually the broadest, but the 



one on the fourth plate is the highest and most conspicuous of the three; all are si ith and polished, 



while the plate upon which they rest is finely wrinkled. The fifth vertebral plate is Hal or with only 

 a trace of an elevation. The color of these young specimens is brownish yellow or horn color, and the 

 margins of all the plates of the cant pace are thickened and darker than the remainder of the plate. 

 The centres of the costal plates usually bear a small dark dot, around which there is sometime- :i 

 narrow dark ring. 



Attention has already been called to the knob-like tubercles observable on many specimens of 

 ,!/. macrospilota and M. pileata, ami these unquestionably have their origin in structures such a those 

 just described in M. litioralis. In the latter species they seem to disappear with age, but in macrospi- 

 lota and pileata they persist, in the males at least, for many years, increasing in size very little, if at 

 all, but very conspicuous when present. In the hundreds of adult and young terrapin from the 

 Atlantic coast which have come under my observation, nothing approaching this character has been 

 found, and it will therefore serve to divide the genus into two distinct groups. 



