174 Rev. T. Hincks's Contributions towards a 



absence of avicularia. As, however, it agrees in the moi"e 

 essential elements of structure with this tribe, the absence of 

 the appendages should hardly separate it from its kindred. 

 In his diagnosis of the family (Onychocellidje) Jullien 

 describes the avicularia as " plus ou moins constants." 



MacGillivray's genus Caleschara is hardly tenable, as from 

 the condition of his specimens he has been unable to give in 

 his diagnosis a sufficient indication of the distinctive charac- 

 ters. The " generic character " is not such as to enable the 

 student to appreciate the peculiarities of the type. Apart 

 from what relates to the habit of growth and other non- 

 essential points, there is nothing but the following clause : — 

 " Front calcareous, except a small part anteriorly, which is 

 membranous." 



According to ordinary usage a genus so constituted must 

 give place to one founded on a diagnosis sufficient for identi- 

 fication. Jullien's Onychocella with a very slight revision 

 and somewhat wider scope would include Memhranipora 

 antiqua, Busk, and kindred forms, as well as Caleschara. 

 Busk (in his ' Challenger ' Beport) adopts MacGillivray's 

 name, and associates it with a new generic character. The 

 whole subject requires fresh treatment. 



Ibid. (p. 41 Sep.). 



Note on Membranipora transversa, Hinchs ( = M. cincta, 

 Hutton). 



This form seems to be nearly allied to Onychocella and 

 Caleschara. The membranous ectocyst bears the orifice, and 

 below it a calcareous wall passes down from the elliptical 

 opcsia to the base of the cell, dividing it into two chambers*. 



Ibid. (p. 43 Sep.). 

 Vincularia ahyssicola^ Smitt. 



The old genus Vincularia was founded on the erect sub- 

 cylindrical habit of growth, and is now superseded f. The 

 present species is the type of the genus Smittiijora^ Jullien, 

 but in my judgment should be transferred (as I have already 

 stated) to Onychocella, Jullien, revised. 



* On page 42 (sep.), line 15 from the top, /or strong read stony. 



t Busk indeed has retained the name in the ' Challenger ' Report, but 

 has connected with it a new detinition. He assigns it to a genus " inter- 

 mediate between Mitropora and Steyanopdrella,^^ and icith a cylindrical or 

 polyyonal habit of yrotcth. Such a genus is quite inconsistent with the 

 later views of classitication. 



