in the young female the 2 nd joint is still but a little more than one and a half as 

 Ion e as the i st . 



& 



28. Alpkeus frontalis H. M.-Edw. 



Alphcus frontalis H. M.-Edw., J. G. DE Man, Siboga Exp., Monogr. XXXIX a\ Part II, 

 Family Alpheidae, 191 1 (text) p. 369, 19 1 5 (plates), PI. XVII, fig. 79 — ygo. 



Telok Berandang, Pulu Babi (2° 7' N., 96 40' E.). 1 young male collected April 1913 by 



Mr. E. Jacobson. 

 Sinabang, Simalur. 1 adult male and 1 adult ova-bearing female collected February 1913 



by Mr. E. JACOBSON. 

 Telok Dalam, Nias. 1 adult ova-bearing female collected by Dr. KLEIWEG DE Zwaan. 

 Stat. 133. July 25/27. Anchorage off Lirung, Salibabu-island. 1 young female. 



In the young" male, long 22 mm., from Pulu Babi the small cheliped is situated on the 

 right side ; the chela is 8 mm. long (palm 4,5 mm., fingers 3,5 mm.), the dactylus is 2 mm. 

 broad and the palm 3,8 mm. high. The front resembles my figure 79, but on either side of 

 the median emargination the frontal margin is straight, not at all concave. 



The female from Sinabang is 41 mm. long, the male 38 mm. In the male the front 

 resembles fig. 79, but on the right side the frontal margin is straight, not concave, in the 

 female, like in the female from Nias, it agrees with the figure 79 a, the front being more 

 prominent, rounded, not emarginate, in the middle, with the lateral emarginations distinct ; in 

 the young specimen from Stat. 133, finally, the frontal margin is straight, without emarginations. 



29. Alpkeus bidens (Oliv.). 



Alpheus bidens (Oliv.), J. G. DE Man, Siboga Exp., Monogr. XXXIX a\ Part II, Family 

 Alpheidae, 191 1 (text), p. 371, 1915 (plates), fig. 80 — 8o<r. 



Stat. 144. August 7/9. Anchorage north of Salomakiëe-(Damar)-island. 45 m. Coral bottom 

 and Lithothamnion. 1 young specimen, that has lost all the legs except one 

 of the 2 nd and one of the 4 th pair. 



Stat. 172. August 26/28. Anchorage between the island of Gisser and Ceram-Laut. Reef. 

 1 young specimen, that has lost all the legs excepting those of the 4 lh and 5 th pair. 



30. Alpheus anchistus de Man. PI. III, fig. 16 — i6<r. 



Alpheus sp., J. G. DE Man, Siboga Exp., Monogr. XXXIX a', Part. II, Family Alpheidae, 



1911 (text), p. 3S3, 1915 (plates), PI. XIX, fig. 85 — 85 £. 

 Alpheus anchistus J. G. de Man, in: Zoolog. Mededeelingen, uitgeg. vanwege 's Rijks Mus. v. 



Nat. Hist. te Leiden, 1920. Dl. V, Afl. 3, p. 108. 



Stat. 181. September 5 '11. Ambon-anchorage. 54 m. Bottom mud, sand and coral. 1 male and 

 1 egg-bearing female. 



The two specimens are of equal size, about 20 mm. long from tip of rostrum to tip 

 of telson, a little larger than the specimen from Stat. 51, that was described by me in my 

 work on the Siboga Alpheidae as Alpheus sp. : this specimen from Stat. 51, that is lying 

 before me and that belongs to the same species as these two from Ambon, measures only 



