35i 



III b. Cri?iitus subgroup. 



16. AlpJieus Alcyone de Man (Charact. emend.). 



Alpheus alcyone}. G. de Man, in: Abhandl. Senckenberg. Naturf. Gesell. Bd. XXV, 1902, 



p. 870, Taf. XXVII, fig. 61. 

 Alpheus alcyone G. Nobili, in: Buil. Scientif. France et Belgique, XL, 1906, p. 32. 

 Alpheus aculeipes H. Coutière, Alpheidae Mald. and Laccad. Archip. 1905, p. 892, PI. LXXIX, 



fig- 3i- 



Stat. 43. April 4/5. Anchorage off Pulu Sarassa, Postillon-islands. Depth up to 36 m. Coral. 



1 young specimen. 

 Stat. 99. June 28/29/30. 6° f '.5 N., 120° '26' E. Anchorage off North-Ubian. 16—23 m. 



Lithothamnion. 1 male. 

 Stat. 282. January 15/17. S°25'.2S., i27°i8'.4E. Anchorage between Nusa Besi and the N.E.- 



point of Timor. 27 — 54 m. Sand, coral and Lithothamnion. 1 young male and 



1 egg-bearing female of small size. 

 Stat. 285. January 18. 8°39'.i S., I27°4'.4E. Anchorage South coast of Timor. 34 m. On the 



limit between mud and coral. Lithothamnion. 1 young male and 1 egg-bearing 



female of small size. 

 Stat. 299. January 27/29. io°52'.4S., I23°i'.iE. Buka- or Cyrus-bay, South-coast of Rotti- 



island. 34 m. Mud, coral and Lithothamnion. 1 young male and 2 egg-bearing 



females of small size. 



One of the four type specimens from Ternate on which A. Alcyone was established in 1902, 

 is lying before me. lts examination proved i° that the ischium of the legs of the 3 vd and 4 th 

 pairs is armed with a small movable spine and 2 that the dactyli of these legs are biunguiculate, 

 presenting a small secondary claw at some distance from the tip. In both characters this species 

 fully agrees with A. aculeipes Cout. from the Maldive and Laccadive Archipelagoes and in 

 my opinion these two species are therefore identical. According to Professor Coutière's description 

 the fingers of the larger chela should measure one-fourth of its length, but in his figure 3 1 they 

 appear half as long as the palm, j'ust as in A. Alcyone. One of the largest specimens is the 

 male long 13 mm. from Stat. 99, according to Nobili, however, A. Alcyone attains a length 

 of 26 mm. In this specimen the 2 ud antennular article appears a little more than one and a 

 half as long as the visible part of the i 5t , the antennal peduncle reaches by the length of the 

 3 rd article beyond the tip of the antennular peduncle, the scaphocerite, decidedly shorter than 

 the carpocerite, appears as long as the antennular peduncle and the blade hardly reaches 

 beyond the 2 nd article of the latter. The stylocerite which is widened in its basal part, is but 

 little shorter than the i st article. Basicerite unarmed. Penultimate joint of the external maxillipeds 

 one and a half times as long as broad; terminal joint twice as long as the penultimate, 1,2 mm. 

 long and 0,36 mm. broad, almost 4-times as long as broad. Large chela 8 mm. long, fingers 

 in proportion to the palm as 3:5; palm 3,2 mm. high. The carpal segments of the 2 nd legs 

 are 0,44 mm., 1,56 mm., 0,38 mm., 0,4 mm. and 0,56 mm. long; the 2 nd segment is 3,5-times as 

 long as the i st , the 5" 1 one-fourth longer than the i st . Chela 1,06 mm. long, fingers one and 

 a half as long as the palm. 



In the legs of the 3 rd and 4 th pairs the ischium carries a small movable spine. Merus 

 of 3 rd legs 4-times as long as wide, posterior margin of the inner surface armed, along its 



219 



