32 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
M. rectus anterior (internus) has its origin around the cartilaginous _ 
rod mentioned in the preceding paragraph, a little 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, fiz: 11, ré‘a.). 
Mm. obliquis dorsalis and obliquus ventralis. Both oblique muscles 
(ob. d., ob. v.) arise at about the same level along the cartilaginous bar 
which is a continuation of the interorbital septum, their fibers diverg- 
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 dorsal 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 distine- 
tion in innervation occurs (Plate 5, fig. 12, IV). 
Somewhat in contrast with the uniformity of the six principal eye 
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 zwel | 
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 connee- ” 
tion with the ciliary nerves (p. 46). 
M. depressor palpebrae inferioris. This is the muscle first deseribed 
by Bojanus (719) for the turtle as the m. palpebralis, and later by — 
Fischer (’52) as the m. adductor maxillae, and finally by Weber (77) | 
