THE STAEFISH SOLASTER ENDECA. 49 



ertilisation can be induced without difficulty if specimens are available from which 

 portions of testis can be removed and shredded into the vessel containing the ova. 



It is not satisfactory, however, to cut out portions of the female gonad for obtaining 

 ova. A great deal of waste material is introduced into the hatching- vessel, and, worse 

 than that, the eggs hardly ever come out clean, but are still surrounded by follicle-cells 

 and other debris. 



In calm weather, in certain localities near the Millport Station, one may come across 

 floating larvae of Solaster towards the middle and end of April. I have gathered them 

 on three occasions in the channel between the Station and the Fairlie shore. I failed, 

 however, entirely to induce these larvae to undergo metamorphosis. This circumstance, 

 along with the fact that many of them when taken showed minor abnormalities of 

 growth, would lead to the inference that it is chiefly unhealthy larvae which come to 

 the surface of the sea. They are soft and readily break up against the cloth of 

 a tow-net. In gathering them from the surface the best way is to lift them one 

 by one with some water in a dipper. 



The two sets of fertilised eggs obtained in the manner previously described were 

 kept, all through, in their original tanks, specimens being taken from time to time for 

 examination and preservation. In a week or so, as I had to return to Glasgow, about 

 twenty were put into each of two small glass aquaria which I took up with me to the 

 Embryology Laboratory at the University. Throughout the succeeding months an 

 easy circulation of sea-water was maintained in the hatching-tanks at the Station, the 

 incoming current being filtered by tying over the nozzle a bag of fine-meshed cloth, 

 which was cleaned out from time to time. It soon became necessary to guard against 

 escape of the young larvae, when they began to leave the surface and swim throughout 

 the tank. One had accordingly to furnish the inner end of the syphon with a filtering 

 surface, off'ering no bar to the outflow, but rendering the current so Aveak that the 

 larvae would not be injm-ed by being sucked against the cloth. This was done by 

 attaching a very large filter-funnel to the end of the syphon, the mouth of the funnel 

 having tied over it a piece of tow-netting material of moderate mesh. Many larvae 

 came to rest against this surface, but a little disturbance of the water near them from 

 time to time sufiiced to clear them ofi" without injury. I cannot speak too highly of the 

 care and attention paid to the brood all through by Mr. John Peden, the Laboratory 

 Attendant at the Station. 



The tanks employed were of the enamelled fireclay kind, which have proved so 

 useful since they were fitted up in the Millport Station about ten years ago. Their 

 contents remained sweet all through, and their smooth surfaces gave suitable attach- 

 ment to the larvae when they reached the fixation stage, besides being excellent ground 

 for the young Starfish to travel over after metamorphosis was finished. 



Now, at the beginning of November 1910, four * specimens are still alive and 

 * The last of these survived till February 1911. 



VOL. XX. — PART I. No. 7. — February, 1912. H 



