562 THE VOYAGE OF H.M.S. CHALLENGER. 



The telson (fig. 3z) is narrow, tapering, armed with a spine at each posterior angle, 

 and a few long hairs between them ; dorsal surface smooth. 



Habitat. — Station 162, April 2, 1874; lat. 39° 10' 30" S.; long. 146° 37' 0" E.; 

 off East Moncceur Island, Bass Strait ; depth, 38 fathoms ; bottom, sand and shells. 

 Two specimens. Dredged. 



Dr. Stimpson obtained his specimens from a coral reef near the Island of Tahiti, at 

 the depth of 1 fathom ; and Heller records it from the same locality. 



Observations. — Our specimens appear to differ from Stimpson's description, in 

 having the joints of the peduncle of the first pair of antennae subequal instead of the 

 second being twice as long as the first, as that author has described it. Although the 

 one in the Challenger collection was taken south of Australia, and Dr. Stimpson's at 

 Tahiti, I do not think that the slight differences warrant a specific separation. 



Alpheus biunguiculatus, Stimpson (PI. CI. fig. 4). 



Alpheus biunguiculatus, Stimpson, Proc. Acad. Nat. Sci. Philad., p. 100, 1860. 



„ charon, Heller, Sitzungsh. math.-nat. CI. k. Akad. Wiss. Wien, Bd. xliv. p. 272, Taf. iii. 



figs. 21, 22. 

 „ ,, Heller, Reise der Novara, Crust., p. 107. 



Rostrum and supraorbital teeth subequal in length. 



First pair of antennae a little longer than the carapace. 



The second pair a little shorter than the entire animal ; the peduncles of each pair 

 being subequal, that of the second reaching a little beyond that of the first. The 

 stylocerite is longer than the first joint of the peduncle, and the scaphocerite is sharp 

 pointed and as long as the peduncle. 



The larger chela is lost in the two Challenger specimens, the smaller is of narrow 

 form, and has the dactylos and pollex subequal, and about half the length of the palm. 

 The second pair of pereiopoda has the carpos six-articulate, the first articulus being 

 nearly as long as all the rest. Third and fourth pairs having the meros unarmed, the 

 propodos furnished with small spines, and the dactylos biunguiculate. 



Telson broad, slightly tapering to the extremity, which is convex, fringed with hairs 

 and armed with two small spines at the angles, and two others on the lateral dorsal 

 surface. 



