STRUCTURE OF SEVERAL FORMS OF LAND PLANARIANS. 281 



abundance of nematocysts, and that the mouth is simply elongate 

 cylindrical, as in Rhynchodemus, 



Its wriggling motion seems to point to the occurrence in it of 

 greatly developed external longitudinal muscular bundles all over 

 the body surface, as in Dolichoplana. 



Land Planarian of Manilla — Dolichoplana striata. 



I obtained three specimens of a land Planarian, for which I 

 propose the above name, at Manilla, from a resident in the city. 

 The Planarian is most remarkable for its great length and pro- 

 portionately small breadth. The longest specimen of the three 

 in the contracted condition in spirit was 19'5 cm. in length, and 

 the shortest 12 mm.; while the average breadth of the specimens 

 was only 3*5 mm., and the thickness 2 mm. 



The Planarians are long, narrow, flattened and band-like, 

 tapering rapidly to a blunt point at either end. The measure- 

 ments of the three specimens, showing the position of the mouth 

 and generative aperture, are as follows : 



a. b. c. 



Anterior extremity to mouth. Distance . 5'25 cm. . 5'5 . 6"5 



Mouth to generative aperture. Distance 5"5 „ . 6"1 . 4:'7 



Generative aperture to tail. Distance . 9'25 „ . 5"5 . 47 



Totallengths . 20-0 17-1 159 



The relative positions of the organs thus vary very much in 

 the difi^erent specimens, probably because of unequal contraction 

 due to the action of the spirit. 



The bottle containing the specimens unfortunately got broken 

 on board the ship in a gale of wind, and the specimens dried 

 up, and are now unfit for anatomical examination ; but some few 

 sections had been prepared before the accident, and thus some 

 facts as to the anatomy were determined. 



Notwithstanding the extreme length of the body the ovaries 

 are situate near its anterior extremity, as in Rhynchodemus, and 

 hence the oviducts have to traverse an enormous distance in 

 order to reach the uterus. They must be 9 or 10 cm. in length. 



A single pair of eyes only is present, as in Ehynchodemus. 

 These are placed laterally, close to the anterior extremity. 



The genus is especially remarkable for the extraordinary develop- 

 ment in it of the external longitudinal muscular layer which occurs 

 all over the body, being especially marked in the dorsal region, 

 as will be seen from Plate XX, fig. 25. The longitudinal muscular 

 fibres form very compact well-defined bundles, which are con- 

 spicuous in transverse sections of the animals, and are separated 

 from one another by stout radial muscular bundles. The 



