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Show 1905.] ANATOMY OF THE FERRET-BADGER. 23 The posterior cerebellar arteries are asymmetrical in their origin from the basilar, the left being considerably in front of the right. The middle cerebellar arteries arise in front of the sixth nerve. § Some Notes on the Muscles. The muscular anatomy of the Carnivora has been lately treated of in an exhaustive fashion by Messrs. Windle and Parsons*. As a supplement to that paper (which does not deal with Helictis) I am able to offer a few notes upon the musculature of Helictis ;personata. The Sterno-mastoid consists from the very beginning of two parts : the larger of these is inserted on to the mastoid next and superficial to the cleido-mastoid muscle; the smaller part crosses the cleido-mastoid and joins the cephalo-humeral. This latter portion of the muscle has been spoken of as a portion of the trapezius, with which, indeed, it is plainly confluent above. The Sterno-hyoid and Ster no-thyroid appear to arise from the sternum as one muscle. I could find no tendinous intersection. The Omohyoid is apparently completely absent. I could find no trace of it. This muscle is usually present in Mustelidte. The Omotrachelian has exactly the relations described by Windle and Parsons. The Rhomboideus profundus, which arises from the supra-spinous fossa of the scapula near to the root of the spine, is a slender muscle inserted on to the atlas deep of the omotracheal. It is perfectly distinct at its origin from the Rhomboideus cervicalis. Its discovery in Helictis gives further support to Messrs. Windle and Parson's belief that the muscle is eminently characteristic of the Mustelidfe. The Rhomboideus capitis has only a single origin in common with the Rhomboideus cervicalis, not the double origin of Ictonyx (a near ally of Helictis) as figured by Windle and Parsons. The Dorso-epitrochlear is contiguous to and hardly if at all distinguishable from the extra head of the Triceps occurring in this as in many other Carnivora. The Dorso-epitrochlear itself is of course part of the Latissimus dorsi; in passing by the scapula it receives a mass of fibres from the lower border of that bone and thence becomes continuous with a sheet of fibres arising from the Teres and constituting, as I imagine, the " extra head" of the Triceps of Messrs. Windle and Parsons, which those anatomists state to be characteristic of the Mustelidse. The Biceps has only one head. Helictis appears to possess two distinct Palmar is Ion gas muscles. The Sartorius is single and fused at its insertion with the also single Gracilis. The Pectineus, often a double muscle, is single in Helictis. * P. Z. S. 1897, p. 370, & 1898, p. 152. |
