290 CATALOGUE OF THE SPECIES OF VERTEBRATA FOUND IN THE 



rated by a notch. The posterior part of the quadratojugal arch forms a wide roof or 

 ledffe overhang-ino" the lower iaw. The teeth are small, acute, and close together. The 

 median and anterior teeth are unknown, as the anterior half of the skull is-wanting. 

 The angle of the lower jaw projects little or not at all beyond the cotylus. The 

 condyle of the quadrate is nai-row and little distinguishable. Between the intercalare 

 and the transverse process of the parasphenoid, is the deep tympanic chamber. It 

 is traversed on one side of the specimen by a curved club-shaped bone, with the larger 

 end truncate and internal. Its tissue is very spongy. It may be the columella auris, 

 but its slender external extremity appears to be continuous with the os intercalare. 

 This may, however, be due to the mode of preservation. 



The surface of the skull has a dense reticulated ffl3ulpture, which is in places radi- 

 ated. It is especially pronounced along the external border of the quadratojugal arch 

 where it develops nodules which are arranged in a serrate manner. Thei-e is a pro- 

 nounced fossa in front of each orbit, which is bounded within by a convex i-idge extend- 

 ing forwards from the orbit. Between these ridges is another deep fossa of the middle 

 regions, whose posterior border is in line with the anterior edge of the orbits. The 

 cranial wall is here very thin. On each side of the supraoccipital bone a sharp process 

 projects backwards and inwards forming a short horn. I do not imagine that the 

 value of this character is more than specific. The external face of the mandible is 

 sculptured, the sculptured surface presenting an obtuse angle upwards, and leaving 

 a narrow smooth face anterior and posterior to the angle. 



iVeaiuremeiits. M. 



Width of skull posteriorly, .138 



" between intercalare bones inclusive, .062 



" " occipital processes " .019 



" " orbits, .039 



(anteroposterior, .017 



Diameters of orbits - „„„ 



(transverse, .OM 



Elevation of occiput from foramen inclusive, .010 



Width of parasphenoid behind transverse processes, .024 



This cranium presents a ciu'ious mixture of defective and excessive ossification. 

 Its form is more depressed than any others of the family. I await the discovery of 

 its anterioi' regions with interest. 



ECTOCYNODON INCISIVUS, sp. nov. 



A. nearly complete but somewhat distorted cranium represents this species. It 

 presents the generic characters of roofed temporal fossae, sculptured cranial bones 

 without lyra, and an elongated tooth near the middle of the maxillary series. 



