A REVISION OF THE GENUS STEGANOPORELLA. 231 



magnilabris to different geuera, but credit is due to this 

 author for having distinctly understood the purpose of the 

 opesiules. In Stegaiioporella distinct '^ opesiules " may- 

 be formed by the concrescence of the median process with 

 the lateral walls of the zocecium. This is specially the 

 case in S. auriculata (fig. 8) and in S. connexa 

 (fig. 6). 



The tube is probably not to be regarded as a median struc- 

 ture, as may be concluded not only from the internal evidence 

 afforded by Steganoporella, but by a comparison with 

 some of its allies. In Siphonoporella nodosa, Hincks/ 

 of which I have been able to examine a specimen (labelled 

 " Australia") belonging to the Manchester Museum, there is 

 a descending cryptocyst, which, as in some species of 

 Steganoporella, joins the basal wall and leaves a con- 

 siderable subopercular cavity into which a tube projects. 

 Although Hincks did not convince himself that this tube 

 opens into the proximal part of the body-cavity (and I have 

 myself not been able to demonstrate this in the dry spe- 

 cimen), there can be little doubt, on the analogy of other 

 forms, of the existence of the communication. The tube 

 arises quite unilaterally from the descending cryptocyst, and 

 is pressed against one or other of the walls of the distal 

 cavity of the zocecium. 



The Manchester collection contains a specimen labelled by 

 Miss Jelly as Steganoporella delicatissima, Busk. 

 Although the original figure of this species ^ gives little idea 

 of its internal structure, Miss Jelly's determination was 

 undoubtedly correct, and I am thus indebted to her for 

 having my attention called to a species which appears to 

 throw considerable light on the structure of Steganopo- 

 rella. Although Mr. Kirkpatrick has been unable to find 

 the actual type-specimen of M. delicatissima, he procured 

 for me a fragment of the type-specimen of the Alga 

 (Amansia pinnatifida) on which, as Busk points out, 



• ' Ann. Ma?. Nat. Hist.' (5), vi, 1880, p. 90, pi. xi, fig. 10. 



2 'Quart. Jouru. Micr. Sci.,' N. S., i, 1861, pi. xxxiv, fig. 1. 



VOL. 43, PART 2. NEW SERIES. R 



