506 H. W. NORRIS AND SALLY P. HUGHES 



Dermophis there exists a well-developed compressor muscle of 

 the orbital gland (fig. 14, ego.), consisting of an inner circular and 

 an outer layer of longitudinal or oblique fibers. From the outer 

 layer of the compressor muscle there runs posteriorly and later- 

 ally a muscle (figs. 14, 15, tmpro.) which has its other attachment 

 on the tendon of the temporal muscle (tm.) In most of the species 

 examined it is well nigh impossible to be sure that this muscle 

 slip is not attached to the pterygoid process of the quadrate, 

 along whose border it passes. In Caecilia, however, it is certain 

 there is no such relation. While in Dermophis and Ichthyophis 

 the anterior attachment of the muscle merges indistinguishably 

 with the fibers of the compressor muscle of the orbital gland, in 

 the other species examined, particularly Caecilia, the anterior 

 connections are in close relation to the lateral wall of the skull 

 in such a fashion that it is difficult to decide whether the at- 

 tachment is to the latter, or to the mesial border of the sheath 

 of the compressor muscle. Luther ('14, pp. 8, 69, figs. 1, 64) 

 rightly interprets this muscle slip as an anterior head, 'caput 

 preorbitale,' of the temporal (pseudotemporalis) muscle. In 

 Geotrypetes, at least in the single specimen examined, there is 

 complete lack of the temporal muscle, including this preorbital 

 slip. The latter, when present, is always innervated by the 

 same small branch of the ramus mandibularis V {7nd.l) which 

 supplies the compressor muscle. The compressor muscle of the 

 orbital gland has the characteristics of a levator bulbi muscle, 

 as Luther (I.e.) has stated. As far as topographical relations 

 go, it might be innervated by the oculomotorius, as Marcus 

 states in Hypogeophis, but the strong development of the muscle 

 in Dermophis does not accord well with the vestigial condition 

 of the third nerve. 



In Geotrypetes (fig. 17) the retractor tentaculi muscle is 

 double, or, rather, there are two muscles, one the retractor tenta- 

 culi proper, with its origin in a fossa in the pterygoid process of 

 the basal bone ventral to the Gasserian ganglion and insertion 

 into the base of the tentacle, the other with origin from the 

 sheath of the retractor tentaculi at the level of the optic foramen 

 and insertion by a long slender tendon far anteriorly on the inner 



