84 DR. COLLINGWOOD ON THIRTY-ONE 



Although, however, I never lost an opportunity of examining a shore when I could do 

 so towards low tide, the opportunities for such rambles were necessarily limited. 



And yet, although they appeared to be so sparsely distributed, a fact would come to 

 light every now and then which seemed to point out that they were very abundant in 

 the aggregate. For instance, a single visit to a certain spot would perhaps result in the 

 discovery of some minute organism identical with one found on another occasion at a 

 point separated perhaps by a hundred miles from the first-mentioned locality, or, as was 

 the case in some instances, by the whole extent of the China Sea. How was it that 

 I should stumble upon such an inconspicuous organism a second time at a spot so 

 distant from the first, unless they were abundantly distributed through the inter- 

 mediate spaces ? Doubtless an explorer at the same places would still find many new 

 forms, and leave yet many more for a successor. 



With regard to the Planarians collected by the late Dr. Kelaart, and "included in this 

 collection, it is necessary that I should say a few words concerning how they came into 

 my possession. The late Mr. Albany Hancock, of Newcastle- on-Tyne, bearing from me, 

 in the course of correspondence, that I had collected some marine Planarians which 

 appeared to be new, informed me that he had in his possession a number of drawings 

 of similar animals made by Dr. Kelaart (formerly a Fellow of this Society) from speci- 

 mens collected by himself in Ceylon, and principally at Trincomalee. These drawings 

 were briefly characterized by him in a paper " On some new and little-known Ceylon 

 Invertebrata," published in the Journal of the Ceylon branch of the Royal Asiatic 

 Society. Part of this paper was printed in the * Annals of Natural History ' for 1859 ; 

 but the portion relating to the Planarians was not so published ; nor, need I say, were 

 the drawings puhlished at all. Dr. Kelaart issued a ' Prodromus Faunas Zeylanicse,' a 

 portion of which is in the Society's Library, and which contains the description of the 

 Planarians here figured ; but I have nowhere met in the literature of the Planarians 

 with any reference to either of these publications, which appear to be unknown. 

 Mr. Hancock therefore suggested that if I could publish Kelaart's species along with my 

 own, they would, as he expressed it, " make a very interesting monograph on the 

 subject — would, in fact, make a valuable contribution towards the history of these little- 

 known animals of the eastern seas." He therefore sent me the drawings, which, re- 

 garding them as a testament jointly from Dr. Kelaart and Mr. Hancock, both deceased, 

 I have accordingly submitted to a careful examination, and done my best to distribute 

 them according to the genera and species of the best classification. I may say that, 

 with Mr. Hancock, I consider these drawings are sufficient for identification ; but they 

 are unaccompanied by details, and the descriptions of them are hrief. This is to be 

 regretted, since the value of such drawings depends no less upon the accuracy of the 

 verbal descriptions taken from the living animals than upon the correctness and minute- 

 ness with which they are depicted. Unfortunately the animals are so extremely 

 perishable and delicate, that no means yet devised can possibly exhibit them after 

 death in any thing approaching to their natural appearance or beauty of form and 

 brilliancy of colouring. Good drawings and accurate descriptions, therefore, are of the 

 utmost value and importance; and either one without the other is consequently of 



