1901.] CHLAMYDOPHOllUS TBUNCATUS. 107 



Those observed wei'e: — Levator coiguli oris (text-fig. ld,lev.ang.or.), 

 answering to Hyrtl's muscle of tlie same name (its insertion was 

 destroyed in removing the skin). Retractor n«m (text-fig. 13. r.na), 

 a large fusiform muscle rising from the anterior margin of the 

 zygomatic arch close to the lower border of the orbit and under 

 cover of the levator anguli oris ; it is inserted by a round tendon 

 into the snout. A pair of Zygomatici (text-fig. 13, z. i & z. ii), 

 running pai'allel to one another and to the preceding muscle from 

 the anterior border of the zygoma to the upper lip. 



The Depressor mandibuke (digastric) was, as in Hyrtl's specimen, 

 absent. Macalister describes a very delicate depressor. Windle 

 & Parsons^ mention that this muscle was absent in two specimens 

 of Dasijims examined by tliem, although it is described for this 

 genus by Macalister and Cuvier. It is present in Tattisia. 



The Stylohyoid (text-fig. 14, st.hg.) answers closely to Hyrtl's 

 description and has (as in his specimen) an expanded tendinous 

 connection with the mylohyoid. A connection of the same kind 

 is of such frequent occurrence among other mammals between 

 the central tendon of the depressor and the mylohyoid, that the 

 absence of this stylohyoid-mylohyoid connection in Macalister's 

 specimen, in which there was a definite depressor, suggests the 

 possibihty of a fusion of the depressor with the stylohyoid in 

 Hyrtl's specimen and mine. 



The following muscles belonging to this region were also observed: 

 Buccinator (te'Kt-^g. 13, buc). Masseter (text-fig. Vd,mas.). Tem- 

 poralis. Pterygoidei. Sterna -ma xillaris (text-fig. 14, st.max.). 

 Mylohyoid (text-fig. 14, myh.). Styloglossus (text-fig. 14, st.gl.). 

 Sierno-mastoid (text-fig. 14, st.m.). Cleido-mastoid (text-fig. 14,cZm.). 



Muscles of the Trunk. — The Trapezius consisted of two parts: 

 (i) a continuous sheet (text-fig. 13, ifr. i) with an origin that extends 

 from the occiput to the third lumbar vertebra, and an insertion upon 

 the anterior part of the scapular spine and the base of the acromion : 

 it seems to correspond to the major part of both Macalister's 

 divisions, (ii) a narrow slip (text-figs. 13 & 14, tr. ii) rising from 

 the occiput anterior to part i. and inserted upon the inner surface 

 of the clavicle on a level with the clavicular origin of the deltoid. 

 This answers to Hyrtl's clavicular trapezius. 



Rhomboideus thoracis (text-fig. 13, rh.th.) consisted' of two parts, 

 and differed somewhat in arrangement on either side. On the left, 

 both portions were small, separated from one another by a consider- 

 able interval, and rose respectively from the neural spines of 1,2 

 and 6, 7 thoracic vertebrae. On the right, the posterior part rose 

 from the neural spines of the 6 anterior thoracic vertebrae, and the 

 anterior part from the dorsal mid-line of the neck close along the 

 dorsal margin of the rhomboideus capitis. This latter arrangement 

 corresponds approximately to Macalister's account. The posterior 

 border of this muscle was not, as in Tatusia "^^ overlapped by the 

 latissimus dorsi. 



^ Windle & Parsons : " On the Myology of the Edentata." Proc. Zool. Soc. 

 1899, p. 318. '■•■ Macalister, 1. c. p. 236. 



