94 



FIELD NOTES. 



MAMMALS. 



Rhinoceros Tooth at Ditti" 

 ling^ton, East Yorks. — Whilst 

 walking along the cliffs south of 

 Withernsea recently, I found a 

 fine molar of a Rhinoceros, 2f 

 inches in length, and 5| inches 

 in circumference. Mr. E. T. 

 Newton, F.R.S., kindly informs 

 me that this is a premolar of 

 Rhinoceros antiquatis Blum., = 

 Rhinoceros tichorhinus Fischer. 

 Remains of Rhinoceros have 

 been reported from Sewerby, 

 Kelsey Hill, Bielbecks and Hessle, 

 in East Yorkshire, but are only 

 very rarely met with on the 

 coast. — T. Sheppard. 



— : o : — 

 ECHINODERM. 

 Worm Parasitic in Sea= Urchin. — With reference to a 

 ' Nemertine ' found within the test of a Sea-Urchin at Scar- 

 borough, by Dr. John Irvine, and described by him in the 

 January number of ' The Naturalist ' (p. 6), may I suggest the 

 possibility that this is an example of the Nematode, Ichthyonema 

 grayi, first described by Drs. Gemmill and von Einstow in 

 ' Archiv fiir Naturgeschichte,' vol. LXVIII., 1902, pp. 113-118, 

 a summary of that account appearing in ' Trans. Nat. Hist. 

 Soc.', Glasgow, vol. VL, p. 229. The original specimens were 

 found in examples of Echinus escidentus, and the mature females 

 reached a length of five feet, although specimens supposed to be 

 males, at least one of which generally occurred in the same test 

 as a female, were much smaller, onlj^ from two to six inches in 

 length. The specimens described in those papers were found 

 at various localities in the Firth of Clyde, and Mr. D. C. MTntosh 

 of Edinburgh, informs me that he has observed several speci- 

 mens in tests of the Common Sea-Urchin, Echinus csculentus, 

 dredged by him in the neighbourhood of the Shetland Isles. 

 Except for this species, Ichthyonema is an internal parasite of 

 fishes. — James Ritchie, The Royal Scottish Museum, Edin- 

 burgh, 20th January, 1910. 



Naturalist, 



