32 bulletin: museum of comparative zoology, 



.1/. rectus anterior {internus) has its origin around the cartilaginous 

 rod mentioned in the preceding paragraph, a Httle anterior to the others 

 and dorsal to the optic chiasma. This muscle is flattened out against 

 the median connective-tissue septum which forms the common floor 

 of the orbits, so that the muscles of the two sides are close together 

 and parallel, inclosing between them the cartilaginous bar. It has a 

 wide insertion on the anterior side of the eyeball (Plate 5, figs. 12, 13; 

 Plate 4, fig. 11, rt. a.). 



*Mm. ohliquus dorsalis and obUquus voitralis. Both oblique muscles 

 (ob. d., oh. V.) arise at about the same level along the cartilaginous bar 

 which is a continuation of the interorbital septum, their fibers di^•erg- 

 ing to their respective insertions on the eye ball (Plate 4, figs. 10, 11; 

 Plate 5, figs. 12-14). The dorsal oblique takes origin from two dis- 

 tinct bundles (Plate 4, fig. 11), the ventral thickened edge of the muscle 

 beginning as a separate bundle, which has a tendinous origin an- 

 terior to that of the inferior oblique (Fig. 10 and Fig. 7). As nerve IV 

 reaches the dorsd oblique, crossing the orbit mesad to the dorsal rectus, 

 it divides to innervate by one part this ventral portion, while the rest 

 of the nerve passes across the muscle a little distance to innervate the 

 more dorsal and anterior part. There is in the muscle, however, no 

 apparent separation into two bundles at the level where this distinc- 

 tion in innervation occurs (Plate 5, fig. 12, IV). 



Somewhat in contrast with the uniformity of the six principal e\-e 

 muscles of vertebrates, is the variability in occurrence and structure 

 of the accessory muscles which arise from them. Osawa ('98, p. 536) 

 describes for Hatteria a retractor oculi muscle only, but from his 

 description it is evident that he has found practically the same con- 

 ditions as exist in Anolis, for he states that it is inserted "mit zwei 

 Portionen an der Umgebung der Eintrittsstelle des N. opticus und 

 an der laterale Flache des Bulbus etwa in der Gegend des Aequators." 

 This would indicate the presence of a bursalis muscle included in his 

 retractor oculi. He ('98, p. 537) describes the innervation of m. re- 

 tractor oculi in Hatteria as follows: "Der M. retractor oculi weist 

 in der Innervation eine Eigenthiimlichkeit auf insofern, als er am 

 Ursprung einen Zweig aus dem N. abducens und in seinem weiteren 

 Verlauf mehrere kleine Zweige vom Ganglion ciliare bekommt." 

 The probability of such innervation in Anolis is discussed in connec- 

 tion with the ciliary nerves (p. 46). 



M. depressor palpebrae inferioris. This is the muscle first described 

 by Bojanus ('19) for the turtle as the m. palpebralis, and later by 

 Fischer ('52) as the m. adductor maxillae, and finally by Weber ('77) 



