1869.] LOViN — ON HYPONOME SARSI. 267 



Billings and G/j/ptoaphcerltes of Johannes Miiller; and bifurca- 

 tions of the channels are met with in Sjihceroci/stites and Callo- 

 cystites of Hall. Lastly, the genus Hi/ponome shares with the 

 surviving type of the Crinoidea the radiated form of the body and 

 the simply conical unprotected funnel. The specimen described 

 is from Cape York, Torres Strait. 



Dr. Lutken has sent us the following note on the above : — 



Hupononie S'trs'i, a recent Australian Echinoderm, closely allied 

 to the palaeozoic Cystldea, described by Professor Lov:6n, 

 with some remarks on the mouth and anus in the Crinoidea 

 and Cystldea, as a reply to the note of Mr. Billings, in the 

 December number for 1«68 ; by Dr. Lutken, of Copen- 

 hagen. 



Certainly I was not, as Mr. Billings believes, " mistaken" in 

 stating that, before the appearance of Professor Loven's paper 

 on Leskia, it was merely 'a hypothetical supposition,'' that the 

 •'pyramid" in Cystldea was the mouth. I have allowed that 

 this theory has been very Ingeniously advocated by Mr. Billings, 

 but I cannot allow that it was ever proved " according to the ordi- 

 nary rules of comparative anatomy," — the less so, as Mr. Billings 

 himself confesses its being at variance with that capital fact in 

 comparative anatomy, that in all other Echinoderms the mouth 

 is situated in the very centre of the ambulacral system. This 

 fact cannot be invalidated by the analogy furnished by the sup- 

 posed combination of mouth and vent in palaeozoic Crinoids. 

 This supposition still remains to be proved, or rather it is, as I 

 think I shall be able to point out, completely disproved. It is 

 unnatural, ap I have shown elsewhere years ago. We have 

 instances enough of the mouth becoming a vent, but none of the 

 vent becoming the mouth; and th;it would be the case if the 

 proboscis (the anal tubej of recent Crinoids were also the mouth 

 of the palaeozoic. But we now know well where the mouth lies 

 in these old sea lilies, and Mr. Billings has himself first shown 

 the way that leads towards its discovery ; but of this more after- 

 wards. The first apparently (but only apparently, I believe) true 

 analogy from recent nature, brought forward to corroborate the 

 view of the oral character of the "pyramid" in Cystidea, is 

 really that of Leskla. I therefore regret that I cannot recall 

 my expressions as incorrect, though I am sorry that Mr. Billings 

 (whose labours in this field I, of course, highly value and admire) 



