S. HATTA. 



27 



in the corresponding slope of the main island. The former species is 

 found in the Ishikari River and the Teshiwo River, whilst the latter form 

 is met with abundantly in streamlets in that part of the island. 



Sado, a small island in the Japan Sea off the Peninsula of Noto, is 

 very interesting ; it is the same, as to the Petromyzon distribution, as the 

 localities on the opposite shores of the main island, viz : Noto, Toyama, 

 Niigata, Sakata, &c. 



In the Ryükyü (Loochoo) islands, the Lampreys have not yet hith- 

 erto been found; these seem to be destitute of Lampreys. 



I have not yet explored the Lamprey fauna of Formosa ; this I hope 

 to deal with on a future occasion together with that of the opposite coast 

 on the Asiatic Continent. 



If the above assumption be correct, it is clear that the distribution 

 of the Lampreys in our empire is dependent on the topographical features. 

 The influences of other natural conditions, if such truly act apon the life 

 of the animal, are very little as regards the distribution. 



C. On a Specimen of the Lamprey f rom Siberia. 



I have recently received a specemen of the Lamprey from Eastern 

 Siberia, which was caught in a brook callad Pervaya Rechka, a tributary 

 of the Amur River, not far from the Seaport of Vladivostock. It was 

 taken last summer and sent to me by my friend Mr. Abeno who has 

 resided there for about seven years. He writes to me that the Lamprey 

 is very rare in the neighbourhood of the city, and that he has seen only 

 two individuals during that time of his residence. 



The specimen is just transformed individual and is preserved in good 

 condition in alcohol. It measures 15 cm ; therefere, it is smaller than 

 the larger specimen of L. mitsukurii and larger that! smaller ones 

 among it. The second dorsal fin is continuous with the caudal ; the first 

 and second dorsals are separated by a deep notch. The first dorsal is 

 3 mm high, while the second is 5 mm in height. The distance from the 

 snout to the anterior limit of the first dorsal is 7 cm. The head is about 

 as long as the branchial region or the thorax. The supraoral lamina is 



