On Mammals from Eastern Buenos At/res, &c. 2o9 



36 mm." This " second spot," placed below the middle of 

 the spiny dorsal fin and posterior to the base of the pectoral, 

 is said by Holt and Byrne to occur only in the male. As 

 before stated, there are only two mature specimens of G.fla- 

 vescens in the collection ; these specimens both bore the 

 second spot, and proved on dissection to be males. 



EXPLANATION OF THE PLATES. 

 Plate IX. 



Fig. 1. Larval Gobius minutus 2 mm. in length. X 42. 



Fig. 2. Tail of postlarval Gobius minutus 7 mm. in length. X 42. 



Fig. 3. Head of ditto. X 42. 



Fig. 4. Scale from a specimen of G. minutus 51 mm. in length. X 24. 



Fig. 5. Scale from a specimen of G. niger 61 mm. in length. X 24. 



Fig. 6. Scale from a specimen of G.friesii 81 mm. in length, x 24. 



Fig. 7. Scale from a specimen of G.jeffreysii 60 mm. in length. X 24. 



Plate X. 



Fig. 8. Otolith from a specimen of G. minutus 12 mm. in length, 



captured in July. X 37. 

 Fig, 9. Ditto ditto 33 mm. in length, captured in February. X 37. 

 Fig. 10*. Ditto ditto 45 mm. in length, captured in February. X 37. 

 Fig. 11. Ditto ditto 51 mm. in length, captured in August. X 37. 

 Fig, 12. Ditto ditto 58 mm. in length, captured in August. X 37. 

 Fig. 13. Ditto ditto 64 mm. in length, captured in September. X 37. 

 Fig. 14. Ditto ditto 81 mm. in length, captured in January, x 37. 



XXXIII. — A Collection of Mammal s from Eastern Buenos 

 Ay res, with Descriptions of related neto Mammals from other 

 Localities. By Oldfield ThOMAS. 



(Published by permission of the Trustees of the British Museum.) 



By the kind help of Mr. Ernest Gibson, Mr. C. H. B. Grant, 

 already well known for his mammal collecting in S. Africa 

 for the Rudd Exploration, has recently been enabled to spend 

 a few months making a collection of mammals and birds for 

 the British Museum at the former's ranche " Los Yngleses," 

 in the eastern part of the Province of Buenos Ayres. 



This region has not hitherto been represented in the 

 Museum by any modern specimens except a few collected by 

 myself in 1896 at La Plata, about 120 miles N.N.E. of the 



* N.B. — The otoliths from this onwards were subjected to treatment 

 -with acid (HC1). 



