66 4 



Memoirs of the Indian Museum. 



[Vol. V, 



-oe 



:rj- ov 



■r-t 



-er 



As Harding states, there is little more to mention in respect of the external features 

 of this species. The body, which commonly measures 8 mm. long, inclusive of the 



suckers, by 1 mm. across at the middle, is almost 

 cylindrical, sometimes flattened and of nearly simi- 

 lar breadth for its greater length, though it consider- 

 ably tapers forwards. On some occasions it shows 

 a slight constriction a short distance in front of the 

 genital opening, so that there can be distinguished a 

 neck and a trunk. The anterior sucker is of a circu- 

 lar shape and rather less than half the posterior 

 sucker, which is circular or oval in shape, the diame- 

 ter being about 1 mm. 



So far as I could count with c ertainty, the com- 

 plete somite is, as described by Harding, made up of 

 fourteen rings, and the eleven somites XIII-XXIII, 

 according to Dr. Annandale's note, are each provided 

 with a pair of pulsating vesicles, which in the pre- 

 served specimens have collapsed. 



Dorsally situated on the anterior sucker are found 

 two pairs of eyes which on each side lie so close to- 

 gether as to give the appearance of a single eye. The 

 first pair are directed obliquely forwards, while the 

 second pair are directed obliquely backwards. 



The ground colour is subject to variation, gener- 

 ally being bright or pale olive green. Both dorsally 

 and ventrally the body appears more or less dark 

 brown on account of irregular pigments present all 

 over in reticular distribution, leaving only a small 

 space free on the mid-lateral sides of each somite. 

 As has been mentioned by Harding, the anterior 

 sucker shows three transverse pigment bands on the 

 dorsal surface, one band following the junction with 

 the body, one near the anterior tip and a third and 

 broader one between the two, in the posterior part of 

 the sucker, which contains the eyes. Medially these 

 bands are traversed by a longitudinal band. The 

 posterior sucker is marked with seven pairs of radiat- 

 ing pigment bands, corresponding to the seven som- 

 ites of which it is composed. 



The epidermis, as is well known in Piscicola, 



presents the most primitive arrangement of cells 



which are not closely packed. Below the epidermis, in the parenchyma, are found 



enormous quantities of pigments which are widely distributed as mentioned above. 



XII 



XIII 



XIV 



XV 



XVI 



XVII 



XVIII 



XIX 



XX 



XXI 



— St 



e 



XXV 

 XXVÎ' 



xxvir 





-~an 



Fig. i. — Diagrammatic represen- 

 tation of the organization of Pis- 

 cicola olivacea, Harding, as seen 

 from the dorsal side. 



an = anus, eg = cephalic ganglionic 

 mass, cr = crop, in = intestine, m — 

 mouth, oe = oesophagus, ov = ovary, 

 ph = pharynx, sg = salivary gland, 

 st = stomach, t = testis, vd = vas de- 

 ferens. 



