ix, d, 4 Cowles: Palaemons of the Philippine Islands 397 



Matthai is correct concerning some species of Macrobrachium, this 

 specimen may be a polymorphic form of Palaemon latidactylus. 



Specimens 73, 128, and 371 were purchased in a Manila market 

 by the author, and it is supposed that they were collected in 

 Pasig River, near Manila; No. 593 was taken from the filter of 

 the Bureau of Science, which receives its water from the Manila 

 water supply; No. 1485 was collected by A. L. Day from the 

 settling basin of the Manila water supply; Nos. 1499 and 1500 

 were collected by Alvin Seale and Urbano Villamor in a small 

 river at Jaro, Leyte; the 3 specimens, No. 1451, were collected 

 by E. H. Taylor in a natural canal connected with Agusan River, 

 Mindanao. 



Palaemon sp. Plate III, figs. 11 and lla-c. 



Two old male palaemons collected from the Manila water 

 supply may be representatives of a new species, although the 

 specimens possess certain characters which suggest Palaemon 

 esculentus Thallwitz and especially Palaemon oenone de Man. 51 

 However, as I have not seen specimens of either of these species 

 and as I have 2 specimens of nearly the same size only, I do not 

 feel justified in describing them as a new species. 



The description which follows, except when otherwise stated, 

 applies to the largest individual whose body length is 59.5 milli- 

 meters and whose carapace length is 20 millimeters: The body 

 length of the smaller specimen is 58 millimeters and the length 

 of the carapace, 19 millimeters. The rostrum which curves down 

 slightly, fails by a considerable distance to reach the tip of pe- 

 duncle of the first antenna. Of the 15 almost evenly spaced 

 teeth on the dorsal border of the rostrum, 7 are situated on 

 the carapace, and of these the first 3 are smaller than those 

 anterior to them. The first tooth is situated back of the orbit 

 a little more than one-third of the distance from the orbit to 

 the posterior border of the carapace. On the lower border of 

 the rostrum are 2 teeth. From this description it is evident 

 that the shape and dental formula of the rostrum and the arrange- 

 ment, size, and position of the rostral teeth very closely resemble 

 those of Palaemon oenone and not so closely those of Palaemon 

 esculentus. The rostrum of the smaller specimen is similar to 



the description given above, but the dental formula is only -^ 



with the seventh tooth directly over the posterior edge of the 

 orbit. 



51 Abh. Senckenbergischen Naturforsch. Ges. (1900), 25, 784. 



