On new Mammals from Ecuador and Venezuela, 451 



Catlocarpio siamensts. 



Head large, flat above ; ejes visible from below and not 

 from above ; mouth wide, terminal, maxillary extending to 

 below anterior border of eye ; lower lip much develope 1, but 

 interrupted at the mandibular symphysis ; nostrils large ; eye 

 65 times in length of head, 8 times in interorbital width ; a 

 much developed thin dermal fold bordering the gill-cover. 

 Gill-rakers a little longer than gill-fringes, 110 on anterior 

 arch. Depth of body equal to length of liead^ 2| times in 

 total length. Dorsal IV 9, originating above base of ventrals, 

 at equal distance from the end of the snout and the base of 

 tiie caudal ; first branched ray longest, f length of head. 

 Pectoral a little shorter than ventral, a little more than | 

 length of head, reaching beyond base of ventral ; latter fin 

 reaching vent. Anal IV 5. Caudal deeply forked, middle 

 rays not half as long as outer. Caudal peduncle as long as 

 deep. Scales 39 ^ : 5 series of scales between lateral line 

 and ventral ; lateral line complete. Bronzy bro'.vn above, 

 silvery beneath ; fins blackish towards the end. 



Total length 210 millim. 



TLe British Museum has received from the Royal Siamese 

 Museum, through its Curator, Mr. S. S. Flower, a single 

 specimen of this highly interesting new fish. It was procured 

 in the Menam River. 



LXX.— O/i Seven new Small Mammals from Ecuador and 

 Venezuela. By Oldfield Thomas. 



The British Museum owes to the generosity of Mr. Ludoyic 

 Soderstrbm, Her Majesty's Consul at Quito, a small collection 

 of mammals from Ecuador, and, besides several species 

 obtained by Mr. L. Fraser and described by Mr. Tomes, 

 there are examples of the two new species described below, 

 Mr. Soderstrom was also the discoverer of the Ichthyomys 

 Soderstromi and Fudua mephistopheles, described by Mr. de 

 Winton in 1896*. I have also taken the opportunity of 

 describing some further new species recently received from 

 Venezuela. 



Reithrodontomys Soderstromi, sp. n. 



Size fairly large, nearly equalling that of R. costaricensis, 

 Allen. General colour dull greyish fawn, not nearly so rufous 

 * P. Z. S. 1896, p. 507. 



