willard: cranial nerves of anolis carolinensis. 33 



as the m. depressor palpebrae inferioris. Bradley (:03), in analyzing 

 the musculature with a ^•iew to explaining its relation to the mastica- 

 tory movements, recognizes in several of the lizards a double function 

 for this muscle, as suggested by the fact that some of its fibers are 

 inserted on the lower eyelid, while others appear to have their inser- 

 tion in the " fibrous membrane circumscribed by the pterygoid, pala- 

 tine and the transverse bones " (p. 481) . This is also brought out more 

 fully by Bruner ( :07),^ who, in looking in the head musculature for an 

 apparatus to control the flooding and distension of the orbital blood 

 sinuses, discovered that a part of this muscle was completely differ- 

 entiated into a m. protrusor oculi, and records its occurrence in eleven 

 lizards, including iVnolis. It is apparent, however, from a study of 

 several series of sections that the two are not completely distinct 

 morphologically in Anolis, as the following description will indicate. 

 It seems probable, however, that the two functions as described by 

 Bruner are here subserved. The following is the condition in Anolis : — 

 the thin layer of striated muscle (Plate 3, fig. 7; Plates 4, 5, figs. 

 11-15, protru. oc, dep. palh. if.) which lines the floor of the orbit 

 ventromesad to all other orbital structures has two distinct origins; 

 one (protru. oc.) is from a slender tendon attached to the membranous 

 wall of the cranium just anterior to the bony part on a level with the 

 Gasserian ganglion (Plate 3, fig. 7; Plate 6, fig. 16). This tendon 

 passes down mesad to the columella (epipterygoid) and is continuous 

 with a muscle band which lies closely applied to the membranous 

 region (Plate 5, figs. 14-15) referred to by Bradley. \Mule some of its 

 fibers may be inserted here, most of them continue and spread out to 

 form the anterior part of the broad palpebral muscle with insertion 

 on the lower lid. This is best shown in the dissection (Plate 3, fig. 7). 

 The second origin, ventral to that of the first, is from the fascia on the 

 ventral face of the bursalis muscle; this band crosses ventral to the 

 posterior rectus muscle (Plate 3, fig. 7; Plate 5, fig. 15, dcp. palp, if.) 

 and turns sharply to form the posterior half, or more, of the palpebral 

 muscle. The two bundles of origin include between them the jugular 

 vein and suborbital sinus of the same side. The innervation of these 

 muscles favors the view of a double function, and suggests for a part 

 of it at least a more visceral function, such as that assigned to it by 

 Bruner. This will be described in detail in connection with the ac- 

 count of the nerves (p. 50). 



■ Bruner does not mention the earlier recognition of this muscle by Bradley. 



