﻿I 



DR. J. MURIE ON THE THREE-BANDED ARMADILLO. II7 



(partiaUy visible, fig. 51) are the upper nasal passages, here rather narrow than otherwise. 

 Outside them and in front is the reduced continuation of the frontal cells. The shell 

 of the hone in the entire area spoken of is thin, and remarkably so at some parts. Thus 

 whatsoever be the office of these air-cells, every provision is made for them, as they claim 

 a maj or share of the front of the skull . 



Prof. Gervais's cast , in outline of the cranial cavity of Tolypeutes tricinctus (aheady 

 mentioned) amply characterizes the figure of the interior osseous basal view of that of 

 T. conurus. There is a broad trapezoidal olfactory section, a lengthened slightly forward 

 tapering cerebral or mid division, and a short but wide cerebellar portion. The level of 

 the first is considerably higher than that of the second and third. The cribriform plate 

 of the ethmoid is completely cellular in structure ; the crista galli is thick, rounded, 

 centrally ridged, and with a marked upward and forward inclination, the top being 

 perforated by many foramina. The parietal areas are relatively narrow, vertically high, 

 and impressed with but few and faint sulci. In this specimen the transverse suture 

 between the orbito- and basisphenoid has imperfectly coalesced, leaving a linear fissure ; 

 hut, I find, in other genera of the Armadillo its closure is also long delayed. The optic 

 foramina, of fair size, pierce the bone in front of the said suture and the sphenoidal 

 fissures at each side. H. N. Turner remarks, as characteristic of the Dasypodidse, that 

 •* the foramen rotundum is included in the foramen spheno-orbitarium " {I. c. p. 211) ; 

 such appears to be the case in Tolypeutes, though in my T. conurus I may record the 

 presence of a minute foramen midway between the sphenoidal and carotid apertures. 

 Internally this was more notable on the right side ; but although I passed a bristle into 

 it almost 0*2 inch, I could detect no exterior aperture. The reverse was the case on the 

 left side, where interiorly an orifice was barely visible even with a magnifier ; but exteriorly, 

 equidistant between the foramen ovale and the sphenoidal cleft, a foramen of some deptli 

 existed^ but which I could not make out to communicate interiorly. I am left in doubt, 

 therefore, if this be an occluded representative of foramen rotundum. There is a wide 

 and relatively long groove for lodgment of the trunks of the trifacial nerves and the 

 Casserian ganglion. The foramen ovale is more elliptical antero-posteriorly and further 

 distant from the sphenoidal opening than in the larger-skulled Euphr actus {E. villosus). 

 The foramen spinosum is not behind the foramen ovale within the skull, as in the last- 

 named genus, but to the inside, and situate between it and the carotid groove, though 

 exteriorly it opens in front of the foramen ovale. The trihedral periotic has a consider- 

 ably forw^ard elongate apex ; and the fossa behind the prominence of the semicircular 

 canals (equivalent to the sigmoid groove of the lateral sinus in Man) is excavated deeper 

 than in most of the Armadillos. The latter feature tallies with the weU-developed 

 flocculus of the cerebeUum. Lower than and one Hue within the fossa is the scale- 

 covered fissure of the aqugeductus vestibuli ; an emargination of the bone below this, and 

 a trifle in advance, hides the aqu^ductus cochleae. The clefts, viz. foramina lacerum, 

 medium, and posterius, are each long and patent ; a narrow bar of bone separates the 

 ^rge anterior condyloid foramen from the jugular fossa ^ 



^ This and the si^bsequent descriptive footnotes on the bones of the Apar {Dasypm iToly^mte.-] tridncm) arc 

 f^of. Owen'B own comments attached to the specimens presented to the College of Surgeons hy Mr. Charles Darwm 



