DREDGING ON THE COASTS OF SHETLAND. 335 



and that had formed part of the ballast of a vessel bound to Europe. As the 

 corals had lain on the beach for a long time, Chemnitz thought the shells 

 might have been terrestrial, and not marine. Mistakes of a similar kind 

 have been made by modern conchologists — e. g. Halia Friamus. 



M. Hupe, the able and courteous curator of the natural-history collections 

 in the Jardin des Plantes (whose knowledge of the recent Echinodermata is 

 very extensive), published in the ' Eevue et Magasin de Zoologie ' for March 

 1860 a description of another species, under the name of Stilifer Orlignyamis. 

 While examining a specimens of Ciduris imperialis, Lam., from New Holland, 

 he noticed that two of the spines were imusnally enlarged, tumid and irre- 

 gularly spherical; at their base he observed two small vertical shts, like 

 button-holes, placed opposite to each other. A section of these spines 

 showed that in the cavity of one was enclosed an adult Stilifer, and in the 

 other, two specimens, which were also adult, besides several embryonic 

 shells. With respect to the mode by which the Stilifer had thus become 

 enclosed, M. Hupe was of opiuion that the cavities were not made by them, 

 but that the interposition of some part of the mollusk had prevented its being 

 completely imprisoned in the spine during the progress of the growth of the 

 Cidaris, which would otherwise have enveloped and smothered the Stilifer. 

 He was kind enough to show me the specimens ; and theyseemed to present 

 an analogous case to that of Stilifer astericola, which I had examined in 

 Mr. Cuming's collection. 



Lastly, I would cite an excellent monograph by Dr. Fischer, which 

 appeared in the ' Journal de Conchyliologie ' for April last, on the genera 

 Stylifer and Entoconcha (p. 91 &c.). In this monograph aU the known 

 species of Stilifer are redescribed, and a new one (/S. Paulv^cice) well 

 described and figured. According to Fischer, the Entoconcha mirahilis of 

 J. MiiUer, found in Synaptce at Trieste, is probably the fry of some other 

 moUusk. At aU events, we want more information about it. It is almost 

 microscopic. 



But to return to Stilifer. Fischer suspected that it is not a true parasite. 

 He says that the discovery by M. Hupe proves that, although living like a 

 parasite on the tegumentary system of the Eehinoderms or their appendages, 

 the Stilifer does not feed on their substance, as has been supposed. Its 

 nourishment comes with the sea-water through the openings of the cavity 

 which it occupies : perhaps its proboscis may be protruded for the purpose of 

 seeking this noiu-ishment. I need not say that the reputation of Dr. Fischer 

 as a physiologist, especially with regard to the MoUusca, makes any opinion 

 of his on such subjects very valuable. I share his incredulity as to Stilifer 

 being a parasite in the ordinary meaning of the word ; but my impression 

 is that it feeds on the excretions of Eehinoderms, and not on animalcules 

 or other organized and living matter with which sea-water abounds. It 

 has never been found except on Eehinoderms, or imbedded in their rays or 

 spines. All the specimens of Stilifer Turtoni which I have seen in situ (and 

 they have been rather numerous) occupied the upper sides of Echini, in the 

 area of the vent or anal opening. The Echini so infested appeared to be 

 invariably in perfect health and vigour. The Shetland specimen of E. JDr'6- 

 bachiensis was carefully watched by me for more than twelve hours. Its 

 tubular suckers and pedicellarise continued in active although intermittent 

 motion during aU that period. The Stilifers were nestling or slowly crawling 

 about among the spines ; but they did not touch any of the suckers of the 

 Echinus, which, being retractile, could easily have been withdrawn into the 

 test ; nor could I detect either of the moUusks in the act of feeding on the 



