Mr. W. Clark on Lepton Clarkise. 293 



maticum — but PI. VI. fig. 3. a peculiar bone, perhaps os "Wor- 

 mianum; +, (PL VI. fig, 1) nostrils, (PL VI. fig. 2) foramen 

 magnum ossis occipitalis. 



On the vertebral column PL VII. fig. 3. and 4. are represented by — 

 a, a, processus articulares anteriores ; b, neck of the first rib ; 

 c, c, bodies of ribs ; m, m, processus mammillares ; o, o, lower 

 transverse process of the sixth cervical vertebra ; p, p, posterior 

 articular y)rocesses ; q, lower transverse process of the fifth cer- 

 vical vertebra ; r, single lower transverse process of the seventh 

 cervical vertebra ; t, upper or proper transverse processes ; x, costal 

 prominence on the upper transverse process of the sixth cervical 

 vertebra. 



All the figures on Plate VI. and VII. scarcely reduced ^rds. 



Erratum. 

 At page 168, third line from bottom, /or 3^ feet read 5^ feet. 



XXV. — Further Observations on Lepton Clarkise. 

 By William Clark, Esq. 



To the Editors of the Annals of Natural History. 



Gentlemen, Norfolk Crescent, Bath, March 7, 1852. 



I BEG you to insert the following addenda, relative to the specific 

 characters of the new Lepton Clarkia, mentioned in the March 

 'Annals of Natural History,' N. S. vol. ix. p. 191. One of the 

 distinguishing marks of the new species has been already alluded 

 to, — the oblique rounded outline ; but I have omitted to name 

 another equally important, that the side anterior to the beaks is 

 double the transverse length of the posterior one ; whereas in all 

 the other Leptons, of which I have more than a hundred ex- 

 amples, the beaks are nearly central, and they have more or less 

 subangularity at the sides ; therefore the oblique outline, rounded 

 sides, and position of the beaks, are unerring guides to distin- 

 guish the L. ClarkicB from its congeners. The last character is of 

 such value, that it is desirable to add to those already published, 

 after the word " gerente " — 



Latus rostris anterius, quoad longitudinem transversam, duplo, 

 posterius superat. 



I also request to state, that I terminated my last paper in the 

 ' Annals ' above-quoted by observing, " I was all but convinced 

 the Lepton convexum and L. nitidum were identical.'^ This view 

 has been shaken by the acquisition of some intermediate speci- 

 mens. I therefore decline to speak further on this point until 

 the animal of the L. convexum is observed. I have a full, though 

 unpublished account of the L, nitidum, and as a fresh specimen 



