Figure 176. — Mironov's method of recording the rate of 

 water filtration by sea mussel. A — horizontal arm for 

 the suspension of cover slip R; M — mussel; P — platform ; 

 S — scale divided in angles. From Mironov, 1948. 



glass strings from a horizontal arm (A) of a rod is 

 lowered to such a position that the center of the 

 cover slip is exactly in front of the exhalant siphon 

 of the mussel and is perpendicular to the axis of 

 the cloacal current. A thin glass indicator is 

 cemented by canada balsam to the cover slip; its 

 distal end moves along the scale (S) which is 

 divided in angles. The deflection of the indicator 

 is read every 5 minutes. The apparatus is cali- 

 brated by recording the deflection of the glass 

 plate caused by a current of known velocity. For 

 this purpose Mironov used the difference in water 

 levels in the two ac^uaria A and B shown in figure 

 177. Water from A runs through an inverted 

 U-tube into tank B. A small inverted T-tul)e (T) 

 with one end sealed is inserted into the left arm of 

 the siphon (U). The recording assembly of the 



type shown in figm'e 177 is placed in front of the 

 cover slip, and the angles of deflection correspond- 

 ing to the various level differences are read: milli- 

 meters on vertical scales L and Li placed in each 

 tank. The velocity of the current is computed by 

 using the for nulla V = -v'2gH where H is the differ- 

 ence of the heights of water columns in the two 

 connecting tanks and g is acceleration due to 

 gi'avity. The volume is calculated by multiplying 

 the current velocity V by the cross-sectional area 

 of the opening of the siphon (2.4 mm.^ in Mironov's 

 experiments). The average rate of water trans- 

 port was found to be 15 ml./min., or 0.9 l./hr. 

 Mironov's observations, made within 24 hom-s, 

 showed great variations in the rate of water 

 transport which undoubtedly indicated that the 

 experimental animals were disturbed and had not 

 reached the steady state. 



Lack of automatic registration of the rate of 

 discharge is the obvious deficiency of the method, 

 which could be improved by incorporating a me- 



FiouRB 1 77. — Mironov's method of calibrating the angle of 

 deflection of a glass plate by the currents of different 

 velocities. A, B— two aquaria tanks; U — inverted tub- 

 ing acting as a siphon; T— tubing connecting the siphon 

 and the tank A; the horizontal arm of the tubing is 

 placed in front of the swinging glass indicator; L, L,— 

 scales mounted on side walls of tanks to read the differ- 

 ences in water level. 



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FISH AND WILDLIFE SERVICE 



