NO. 2129. PHILIPPINE CRUSTACEANS— HANSEN. 645 



IS. EUPHAUSIA SIBOCae H. J. Hansen. 



D. 5288. July 22, 1908. Off Matacot Point, Luzon. Lat. 13° 

 43' 30" N.; long. 121° E. 115 fathoms. 8.14 a. m. Numerous 

 specimens. 



D. 5553. September 17, 1909. Sulade Island, anchorage. Lat. 

 5° 51' N.; long. 120° 46' 30" E. Surface. 7.28 p. m. Surf. temp. 

 83°. 4 specimens. 



16. EUPHAUSIA FALLAX, new species. 

 Plate 83, figs. la-Id. 



D. 5288. July 22, 1908. Off Matacot Point, Luzon. Lat. 13° 

 43' 30" N.; long. 121° E. 115 fathoms. 8.14 a. m. About 20 

 specimens. 



Type-locality. — D. 5532. August 13, 1909. Off Gigantangan Island, 

 between Masbate and Leyte. Lat. 11° 36' 39" N.; long. 124° 13' 

 30" E. Surface. 7.14 p. m. Surf. temp. 84°. Immense number of 

 specimens. 



D. 5422. March 30, 1909. Off Lusaran Point. Lat. 10° 31' N.; 

 long. 122° 18' 45" E. Surface. 7.17 p. m. Surf. temp. 82°. Many 

 small specimens. 



D. 5233. May 7, 1908. Off Limasaua Island. Lat. 10° 00' 22" 

 N.; long. 124° 45' 06" E. 100 fathoms. 9 p. m. 7 specimens. 



D. 5539. August 19, 1909. Off Apo Island. Lat. 9° 03' 20" N.; 

 long. 123° 24' 30" E. Surface. 7.11 p. m. Surf. temp. 83°. 4 

 specimens. 



Description. — ^This species is very similar and closely allied to E. 

 gihhoides Ortmann, as described and figured by me.^ In reality I 

 have been unable to find any specific differences between the two 

 species in the shape of the frontal plate, the rostrum, the gastric area, 

 the eyes, the antennular peduncles, etc. Third abdominal seg- 

 ment has the dorsal middle of the hind margin a little or somewhat 

 produced, and this produced part is either frequently rounded, or 

 terminates in a smaU and extremely slender spiniform process. 



The male copulatory organs (figs. la-Id) of first pleopods afford 

 some striking characters. The terminal process (p^) has the foot of 

 moderate length and the heel rather short, thick, straight; the 

 process beyond the foot is moderately long, seen from behind (fig. Ih) 

 straight, moderately stout, not tapering beyond the middle, and 

 with the end obtuse; seen from the inner side (fig. Ic), it is somewhat 

 curved forward at the middle, widening from the middle (fig. Id) 

 toward the end, which has two conspicuous incisions dividing the 

 terminal part into three teeth; the median tooth is long, somewhat 

 curved, acute; the posterior tooth is smaller but at least twice as 



I Mem. Mus. Conip. Zool., vol. 3j, No. i, p. 252, pi. 9, figs. 2a-2ft. 



