210 Mr. H. J Carter on 



Lastly the keratose fibre may be generally or partially cored 

 with foreign objects, in which case the vertical fibre is gene- 

 rally the most, and the lateral the least so; but it is a remarkable 

 fact that, throughout the Psammonemata, the arenaceous 

 iibre is frequently so thinly clad with keratine as in many 

 instances to appear to be nothing more than a simple chain of 

 foreign objects. The terms " vertical " and " lateral " are 

 synonymous with Dr. Bowerbank's " primary " and " secon- 

 dary " fibre. 



With these preliminary remarks let us now enter upon the 

 revision of the order Psammonemata after the manner to 

 which I have above alluded, that is beginning with the lowest 

 forms first and working upwards, in which it should be 

 remembered that I am chiefly limited in this respect here to 

 what Mr. Wilson's specimens indicate, as I want to point 

 out, by them too, what is to be found on the south coast of 

 Australia. 



After noticing that which I considered to be the Dysidea 

 Kirkii of Dr. Bowerbank ('Annals,' 1881, vol. vii. p. 374), 

 a summary was given of what had been stated of this as well 

 as the British species Dysidea frayilis, in which was quoted 

 the following passage from Dr. Bowerbank's ' Monograph of 

 the British Spongiadae ' (vol. i. p. 212), viz.: — "In our 

 British species, Dysidea fray His, Johnston, the primary fibres 

 are often as abundantly arenated as those of the Australian 

 species (Dysidea Kirkii), while the secondary ones are only 

 partially filled with extraneous matter." Thus both species 

 wevejibrous, and both the " primary " and " secondary" fibres 

 were arenated, that is contained foreign objects. In short 

 both species were fibrous and all the fibres arenated, although 

 not equally so, which is what I want to insist upon here. 

 Hence 1 was wrong in stating that Dysidea fray His and 

 Sponyelia pallescens, Sdt., were the same ; for by consultino- 

 Schulze's representation (Zeitschrift f. wiss. Zoologie, Bd. 

 xxxii. Taf. vi. fig. 5), which I am able to confirm by havino- 

 a type specimen of Schmidt's S. pallescens, it will be ob- 

 served that " all " the fibre here is not " arenated," but that 

 the lateral or secondary fibre is mostly keratose and homo- 

 geneous, **. e. clear or not cored with foreign bodies, while 

 the vertical or primary fibre is completely cored or arenaceous. 

 My mistake arose from the conulated surface of Dysidea 

 frayilis when dried in its natural state being precisely like 

 that of Sponyelia pallescens. Thus Hyatt was right in sepa- 

 rating Dysidea from Sponyelia, i. e. S. pxdlescens (Mem. 

 Boston Soc. Nat. Hist. 1877, vol. ii. pt. 4, p. 539). Both 



