Terrestrial Planariaiii froin Jiptm^se Ttrritori-s 5 



underneatli the fine basement membrane, is made up of two layers 

 of the outer circular and the inner longitudinal fibres. Separated 

 from this by a zone of tissue is the deep mur^cular system which 

 forms a layer thicker than the superficial and consists principally 

 of two sets of fibres, longitudinal and ciicular; these fibres occur- 

 ring intermingled in the same mass without being arranged in 

 definite layers, liesides, dorso-ventral filn-es are well developed, 

 running between the intestinal branches. 



Tlie mouth-opening lies near the centre of the peripharj-ngeal 

 cavity, in which tlie pharynx is horizontally disposed. The 

 pharynx is of a short cylindrical shape, terminating conically at 

 the free end. The three main trunks of the intestine are provided 

 with numerous latei'al branches which are sometimes bifurcated 

 and sometimes trifurcated. Their direct wall is a single layer made 

 up of high cylindrical cells, each af which contains a great number 

 of coarse, highly refractive granules in the finely granular proto- 

 plasm. vSometimes the cells were observed to be vacuolated in 

 their distal portion. 



Situated near the anterior end of the bod}' is the brain, which 

 is a bilobed organ, sending out numerous nerves. Posteriorly each 

 half of the brain-mass is continuous with one of the longitudinal 

 nerve cords which proceed straight backwards, until finall}^ they 

 extend to the posterior end of the body. The nerve cords are con- 

 nected throughout their entire course by numerous transverse 

 commisures and give off nun:ierous lateral nerves towards the 

 nerve plexus, which lies beneath the outer longitudinal nuiscles of 

 tlie body and extends Completel v round the body. 



The ge-nital opening leads anteriorly into the penis-sheath and 

 posteriorly into the "muskulösen Drüsenorgan", provided with a 

 wall which projects into the lumen in folds. Embedded in the 

 parenchyme around tlie said organ are numerous glands which 

 Tiiake their way into its lumen. 



Numerous testes, ventral in position, are arranged in a single 

 row just outside the longitudinal nerve cords, beginning from be- 

 hind the ovary and ceasing altogether to exist at the level of the 

 pliarynx-insertion. The vasa deferentia, filled with spermatozoa, 



