34 <;EORGE LEFEVRE AND \VINTERTON c. CURTIS. 



badly preserved and the gills in consequence much shrunken. 

 In this event, it is quite possible that the embryo- might have 

 been contracted into a mass in the middle of the water-tube and 

 the mucus, by which they aie surrounded, coagulated in such a 

 way as to cause the appearance of septa stretching between the 

 interlamellar junctions when observed under a low magnification. 

 It is not uncommon to find the embryos contracted in this manner 

 to a greater or less degree as a result of fixation, as may be seen 

 in Fig. 2, in which the mass of embryos has been withdrawn 

 slightly from the inner surface of the lamellae. The fact that he 

 states that the divisions are only present in the gravid gills 

 would lend some degree of plausibility to this explanation. 



ZOOLOGICAL LABORATORY, 



IMVERSITY OF MISSOURI, 

 April 26, 1910. 



