Prof. A. Macalister on tJie Anatomy of tlic Koala. 127 



I have named this minute but beautiful hydroicl after 

 Colonel Stuart Wortlcj, in whose tanks it was first found. It 

 grows along the glass sides of the tank, sending out long 

 creeping shoots, whence the poljpites rise at intervals. 



It has recently appeared suddenly in my tanks, and, I fancy, 

 is not uncommon, though liable to be overlooked through its 

 minute size. 



XIX. — The Muscular Anatomy of the Koala (Phascolarctos 

 cinereus). By Alexander Macalister, M.B., Professor 

 of Zoology, University of Dublin. 



A FINE female Koala was procured from jMr. Gerrard by 

 Prof. Haughton for the Anatomical Museum of the Dublin 

 University ; and as it was in splendid condition for dissection, 

 we were enabled to examine its muscular system thoroughly. 

 As in its anatomical arrangements it is by far the most 

 aberrant form among the Marsupials, I have compiled the 

 following list of its peculiarities, from which it will be 

 perceived that the myology of this animal is full of interesting 

 features. 



The specimen was a salted one ; but its muscles were 

 exceedingly well preserved and easily dissected. She mea- 

 sured 26 inches in length ; and throughout there was a 

 marked disjiroportion in the development of the two sides, the 

 left-side muscles being very much larger and stronger than 

 the right. There was an exceedingly strong panniculus 

 carnosus, which sprang from the outside of the arm, and the 

 fibres of which passed backwards in an arcuate manner to the 

 integument of the sides ; and forward, forming a very thick 

 2)latysma myoides in the neck ; this muscle had a thick rounded 

 anterior border, and terminated by being inserted into the 

 skin along the ramus of the mandible ; and, stretching even 

 above this limit, the facial fibres formed an even sheet over 

 the front of the masseter and the facial artery to terminate in 

 the middle line of the lower lip, the margin of the mouth, the 

 ala of the nose, and the lower margin of the orbicular muscle 

 of the eyelids. 



The platysma on the hinder part of the body displayed 

 nothing of importance ; its femoral attachment was weak. 



The facial muscles were unusually strong, the orhicularis 

 palpebrarum being a simple thick ring, composed of several 

 thick fascicles ; the occipitalis arises from the occipital protu- 

 berance, and passes radiating forwa.rds ; the frontalis, quite 

 separate, arises from the mesial line of the scalp, and runs 



10* 



