574 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Variation was nil or slight in three characters: 

 supraoral cusps; bicuspid circumorals; and the 

 anterior row. The number of cusps on the supra- 

 oral lamina was 2 in all of the 176 specimens from 

 Cayuga Lake and 106 from Seneca Lake. The 

 number of bicuspid circumorals was 8 in 171 

 specimens of a sample of 173 from Cayuga Lake 

 (the other 2 counts were 6 and 9) and in all 75 

 from Seneca Lake. The number of teeth in the 

 anterior row was 3 in all 73 Cayuga Lake speci- 

 mens. In Seneca Lake lampreys the anterior row 

 count was 3 in 164 of 174 specimens; 9 had a count 

 of 4, and 1 a count of 2, which gave a mean of 3.05. 



Other tooth counts exhibited greater variability 

 (table 15; fig. 8). The number of infraoral cusps 

 ranged from 7 to 10 in Cayuga Lake lampreys 

 (average of 8.02) and from 6 to 10 in Seneca Lake 

 specimens (average of 7.69). In specimens whose 

 infraoral cusps had been worn down, the outer 

 covering was ready to be sloughed off. Invari- 

 ably the distal ends of the lamina in these speci- 

 mens were so constricted as to make it difficult to 

 count the cusps. Removal of this outer sheath, 

 however, exposed the underlying sharp, distinct 

 cusps that could be counted accurately. 



The number of teeth in the circumoral row aver- 

 aged 18.3 for both Cayuga Lake and Seneca Lake 

 samples. The number of circumoral teeth ranged 

 from 15 to 22 in Cayuga Lake specimens and from 

 16 to 20 for Seneca Lake specimens. Undoubt- 

 edly the greater number of specimens examined 



from Cayuga Lake (174), as opposed to 75 from 

 Seneca Lake, contributed to the greater range of 

 this character observed in the Cayuga Lake 

 sample. 



The number of teetli in the lateral row varied 

 little. Cayuga Lake specimens had an average 

 of 7.3 lateral teeth (range, 5 to 8). Seneca Lake 

 specimens had significantly fewer teeth in the 

 lateral row, an average of 7, with extremes of 6 

 and 8. 



Denticulations on the lingual lamina are well 

 developed and never seemed to be so dull or worn 

 as the circumoral teeth. For ease and accuracy 

 in making counts of both the transverse and 

 lateral lingual lamina, the tongue was excised. 



The number of cusps on the transverse lingual 

 lamina of Cayuga Lake specimens ranged from 12 

 to 19, and averaged 14.8. In Seneca Lake speci- 

 mens the count varied from 12 to 18 and averaged 

 14.6. This small difference between the two 

 groups was not significant. 



Cusps on the lateral lingual lamina of Cayuga 

 Lake specimens ranged from 9 to 15 and averaged 

 12.6. In Seneca Lake specimens the count varied 

 from 9 to 17, with an average of 12.5. This dif- 

 ference between Cayuga Lake and Seneca Lake 

 specimens was not statistically significant. 



Sea lampreys from Seneca Lake had a greater 

 number of myomeres (average, 72.7; range, 67-76) 

 than Cayuga Lake specimens (average 71.4; range, 

 68-75: table 16). This difference in number of 



' Both left and right lateral lingual laminae are grouped together. The discrepancy In numbers results from broken laminae. 



