FLOROMETRA SERRATISSIMA. 55 



adjoining basals (plate xxvn, figure 1). It is the first plate to appear after 

 the basalia and oralia, the order of appearance of the different plates being 

 thus: (1) the basals and orals; (2) the anal plate; (3) the axillary; (4) the 

 radials; (5) the costals. 



In the specimen from which figure 6 was drawn the costal had appeared 

 only in one radius, that to the left of the anal radius; the radial plate was 

 also found to diminish in size the same way round, and partly also the 

 axillary, which latter was, however, found to be largest in the anal radius. 



The stalk consists of 16 joints, the 4 upper ones being quite short, the 

 middle ones long and cylindrical, with the primary ring slightly prominent, 

 the 3 lower ones quite short; the terminal stem-plate is irregularly lobed. 



In the stage represented in plate xxvn, figure 3, the radialia have just 

 been formed viz, the small star-shaped spicule to the right of the anal 

 plate, while the costal has not yet appeared. Some meshwork is beginning 

 to develop on the oralia and a growth-zone can be observed in the lower 

 part of the oralia and the upper part of the basalia. 



On account of the large size of the anal plate, the adjoining radial plate 

 lies to the right of the median line; there is a beginning absorption of the 

 lower part of the oral plate. 



A slightly older stage is represented in plate xxvn, figure 4. In this 

 specimen one of the basalia was abnormal, smaller and shorter than the other 

 basals and reaching only half-way down, so as not to join the upper end of 

 the stalk. There are 19 joints in the stalk, the middle ones being very 

 elongate and slender. 



The oldest stage represented is that figured in plate xxvn, figure 5. The 

 radials have grown considerably and nearly join one another, separating the 

 orals from the basals. The costals and axillaries have lengthened and now 

 have the appearance of a small arm. The anal plate has apparently not 

 grown and is now pushed out from its original position in the radial midline 

 so as to lie wholly in its own interradius, between the basal and oral plate, 

 while the radial plate has occupied its final position in the mid-radial line; 

 but it is not yet quite symmetrical, the side adjoining the anal plate being 

 somewhat narrower. Some meshwork has developed in the concavity of the 

 orals. The stalk is incomplete in this specimen, but in another specimen 

 only slightly younger there are 23 joints. The terminal plate remains small 

 and unlobed. Plate xxvn, figure 7, represents part of a decalcified specimen 

 (the same as that represented in figure 1) showing the stone canal and pore 

 canal. So far as can be ascertained without sections, the outer pore is closed 

 in this stage. The primary gonad is very small and indistinct. 



