±QS S. W. WiUiston — Restoration of IAmnoscelis. 



Spht naoodon may have been one, or in seeking its food. The 

 teeth and skull remind one much of Labidosaurus with its long 

 prehensile teeth in the premaxillse and front end of the mandi- 

 bles, teeth well adapted for the seizure and retention of soft and 

 slippery invertebrates, for which it may have probed in the mud. 

 That Limnoscelis was piscivorous in habit seems cpiite improb- 

 able. It must have been slow in locomotion, whether on land 

 or in the water, and its prey must also have been slow-moving or 

 stationary. That the creature could have been really burrow- 

 ing in habit seems out of the question ; with its short front 

 legs it could not possibly have excavated burrows for the head 

 to enter. 



The length of the skeleton as restored is just seventy-eight 

 inches, a few inches less than I had estimated it to be. It is 

 possible, however, even probable that in my restoration I have 

 not made allowance for the interarticular cartilages, and that 

 the creature was somewhat longer in life, perhaps fully seven 

 feet. 



It is a remarkable fact that, so far, not a trace of Limnoscelis 

 has been discovered elsewhere than the El Cobre canon, New 

 Mexico ; nothing that can at present be referred to the genus 

 is known from the Pnerco or its tributaries. Of the four 

 known specimens, two are said to have come from low down 

 in the canon, but the specimen collected by myself was found 

 near the top of the fossiliferous horizons, at least two hundred 

 feet above the lowermost beds ; it is possible that this differ- 

 ence in their horizons may account for the minor differences 

 presented by this specimen. It is also a little strange that, so 

 far, no specimen of Sphenacodon or Ophiacodon has been 

 found in the El Cobre canon. It was in this canon that Pro- 

 fessor Case found a specimen of Spirifer rockymontanus, a 

 real Carboniferous fossil, coming probably from an horizon 

 above that of the type of this genus. From all of which it 

 would seem probable that Limnoscelis really lived dining Car- 

 boniferous times. 



University of Chicago, Chicago, 111. 



