10 TKICI.AL) TLRISKl.I.ARIA l-KO.M INDIAN TIBET 



ordinary coftimnar or cuboidal type. It is, however, lieavily ciliated. This narrow ciliated 

 stalk turns ventrall}' and joins the male atrium at the genital pore. A very thin layer of 

 muscles seems to underlie the epithelium of bursa and stalk. 



A sas^ittal section of the copulatory apparatus of one of the 1.25 specimens is shown in 

 Plate I, fig. 7, of one of the K 78 worms in Plate II, fig. 3. Plate I, fig. 8, and Plate II, 

 fig. 1, are successive transverse sections through the second L 25 specimen, showing in 

 Plate I, fig. 8, the entrance of the vasa deferentia into the penis l)ulli with the oviducts at the 

 sides and the wide part of the bursa stalk above; and in Plate II, fig. 1, the male atrium, 

 union of the oviducts, and narrow part of the bursa stalk above. Plate II, fig. 4, is a diagram 

 of the sexual apparatus seen from above. 



The sexual specimens in the collection were taken (in May 21st and June 21st respec- 

 tively. The time of sexual maturity is therefore early summer. One of the L25 specimens 

 taken on May 21st appears to be the ripest of the lot; but presumably the time of sexual 

 maturity depends in part on altitude, those at higher levels maturing later in the season. 



4. Habitat. The worms came from springs, streams, and pools in the high mountains of 

 Kashmir and Indian Tibet. The altitudes of the collecting sites varied from 2500 to 4700 

 meters while in the Stewart expedition the species was taken between 4250 and 4400 m. 

 These are probably the greatest heights at which any fresh-water planarians have ever been 

 found. The temperatures of the habitats are recorded in some cases and, as might be 

 expected, are mostly low, ranging from 7 to 22"C. In three cases the acidity is recorded as 

 pll 7.5-7.6, quite a usual figure for such habitats. The habitat of Polycclis tibetica is very 

 similar to that oi the only known American representative of the genus, Polycclis coronata, 

 which also lives in mountain streams and springs. Although the American species has as yet 

 been taken only at moderate altitudes (below 5000 feet), there is little reason to doubt that 

 it will be found distributed throughout the high mountain ranges of western North America. 

 The only other species which seems to be specifically a high mountain form is Polycclis 

 cormita of Europe which occurs in the streams of the high Alps althougli distributed over a 

 considerable range of altitude. On the other hand some species of Polycclis are lowland forms 

 but the entire genus appears to require rapidly flowing water and stony bottom. 



Second Species 



It seems desirable to make a statement about the secdud species found in the collection. 

 This is represented by three individuals taken at station K 64 at 2080 meters, in a stream under 

 stones. As this is the lowest altitude at which planarians were found, it seems probable that 

 this .species inhabits lower altitudes than does Polycclis tibetica and consecjuently was not 

 taken at any of the higher stations. 



The species is of large size, probably reaching a length of 20 mm., of uniform dark- 

 brown coloration, and w^ith an evident triangular head with auricles. From the size, uniform 

 dark coloration, the shape of the head, the appearance of the digestive tract, and in fact, the 

 general aspect of the form, I am quite sure it is a species of Euplanaria, very close to the 

 three American memljers of Euplanaria which I have called the dorotoccphala group (Ilynian, 

 1931 b). However, in the absence of sex organs, the form cannot be placed taxonomically with 

 any certainty and I therefore forbear to attach a name to it. It has one peculiarity by which 

 future collectors in this region can probably recognize it. The species tends to Ix; four-eyed. 



