218 
Gastrothylax huhalis 
by washiDg in several changes of 70“/o alcohol to which a little l^/o solu¬ 
tion of ammonium chloride had been added, was found to answer best. 
Owing to the imperfect method of fixation the finer histological details 
were not examined. In tracing the various ducts, etc., rough reconstruc¬ 
tions were made. 
The determination of the genus, Gastrothylax, is made at once when 
a transverse section reveals the generic characteristic, viz., a spacious 
pouch, atrium or belly-pocket (“ Bauchtasche ”), which opens anteriorly 
by the atrial pore. A specimen cleared in clove oil confirms the 
determination by showing the position and number of testes, the branched 
gut and the large terminal posterior sucker. 
Fig. 1. Fig. 2. 
Fig. 1. Outline of G. huhalis. M. mouth. A.P. opening of atrium. 
Fig. 2. Outline of contracted specimen of G. huhalis. M. mouth. A.P. opening of 
atrium. 
External anatomy. The parasite is conical in shape with blunt 
anterior end, and has a length of from 8-10 mm. and its posterior 
diameter is about 3 mm.^ The trematode is of a white or light gray 
colour and none of the specimens showed the characteristic red coloration. 
The form varies from an almost cylindrical shape, in fully expanded 
1 Sis specimens gave the following measurements in mm.: 11-5 x 3-75; 12‘5x4; 
10-0 X 4-5 and 9-0 x 4 (contracted specimens); 8'75 x 4-5 (contracted, pear-shaped specimen); 
7'Ox 3-75 (small specimen, slightly contracted). 
