500 Philippine Journal of Science i»i» 



daughters it could be easily seen that the posterior gonidia are 

 larger than the others. The largest and the smallest gonidia 

 in each daughter were measured and the range of diameters 

 found to be from 18 to 38 ^; the largest minimum, 28 /*; and 

 the smallest maximum, 29 p. This specimen contains a number 

 of endophytic algae in various stages of development. 



An arrangement of the gonidia in three symmetrical pairs is 

 shown by Plate I, fig. 5, a photomicrograph of a coenobium con- 

 taining a posterior pair of embryos and two pairs of gonidia. 

 This specimen (No. 12) measured at the time of taking the pho- 

 tograph about 255 by 290 p. Its appearance after three years 

 is so altered by shrinkage and rotation that several hours were 

 lost in hunting for it. It was found to have rotated about a 

 quarter turn to the right and to have shrunken to about 175 

 by 210 fi. The somatic protoplasts are a little over 5 p in 

 diameter, but the thickness of the membrane between the proto- 

 plasts is reduced to about a micron, making the average cell 

 diameter about 6 ^. This gives 3,520 for the estimate of the 

 number of cells. The gonidia still measure, as in the photo- 

 graph, about 55 by 60 fx. One of the anterior pair is slightly 

 smaller than the others. The two embryos are nearly but not 

 exactly at the same stage, the daughter gonidia being in the act 

 of entering through the phialopore in one, and having accom- 

 plished the entry in the other. 



The relative frequency of the different numbers of gonidia 

 in the coenobia on the type slide was estimated by counting the 

 gonidia, or the gonidia and the embryos, or the daughters, in 

 coenobia which had not released any daughters. For this pur- 

 pose a strip across the middle of the slide was passed in view 

 until a hundred counts had been made. There were found : 



1 coenobium containing 3 gonidia ox- daughters. 



1 coenobium containing 4 gonidia or daughters. 



2 coenobia containing 5 gonidia or daughters. 

 34 coenobia containing 6 gonidia or daughters. 

 32 coenobia containing 7 gonidia or daughters. 

 30 coenobia containing 8 gonidia or daughters. 



100 



On this slide, though the nine hundred coenobia were all 

 passed in view twice and many parts of the preparation were 

 seen many times, no mother coenobium was observed to contain 

 any but asexual daughters ; that is, daughters containing gonidia. 



There are six sexual coenobia on the type slide. One of these 

 (specimen 13) is shown in Plate I, fig. 6. In the photograph it 



