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TRANSACTIONS OF THE PLYMOUTH INSTITUTION. 
Some interest attaches to the ear -bones among Cetacea. Accord- 
ing to the late Dr. Gray, they are at least of generic value. I 
therefore give drawings of the ear-bone of the present example, 
and also that of the Risso's Grampus, recorded last year. 
In the Lesser Rorqual the Tympanic and Periotic bones are 
attached to each other, and from the latter are extended two large 
Zygomatic and Pterygoid processes. 
In the ear-bone of Risso's Grampus the Tympanic and Periotic 
bones are nearly equal in size — about an inch and a half in 
greatest diameter — and the articulating processes are only just 
indicated. 
In conclusion, I would point out that the experience of the 
past three years shows that our fauna is much richer in Cetacea 
than might have been expected, and that our Museum might 
be enriched with many valuable skeletons if we had a tank 
suitable for their preparation. 
EAR-BONES OF RISSO'S GRAMPUS. 
(Grampus Griseus.) 
a Tympanic bone. b Periotic bone. 
Greatest width about 1J in. 
