REPORT ON THE CRUSTACEA MACRCJRA. 



547 



Habitat.— Station 93c, July 27, 1873; lat. 16° 57' 15" N., long. 25° 1' W., 

 St. Vincent, Cape Verde Islands; depth, 52 fathoms ; bottom, coralline mud. Nineteen 

 specimens ; ten females bearing ova, and nine males. 



Observations. — This species was found with Alpheus edivardsii, and when mingled 

 with the younger forms, required close observation to be distinguished from them. It 

 bears a close resemblance to Alpheus megacheles, Hadstone, from the English Channel, 

 and which the Rev. Canon Norman states to be Alpheus edwardsii, Milne-Edwards. It 

 differs, however, from the British form, in having a strong tooth on the meros of the third 

 and fourth pairs of pereiopoda. The large chela is very similar, and has the dactylos 

 impinging oblkpiely against the pollex ; but there is a deeply incised notch in the upper 

 and lower margins, which in Alpheus megacheles (PI. XCVII. fig. 4) are smooth. 

 The smaller chela has also a peculiar resemblance in general form, but possesses a narrow 

 crest on the upper surface of the dactylos, which is wanting in the British species. The 

 largest specimen that we have of Alpheus cristidigitus is only 10 mm. in length ; and 

 they are undoubtedly mature, since the females are laden with ova. Alpheus 

 megacheles on the other hand is 50 mm. long ; but this may not necessardy be a specific 

 feature, as specimens of Alpheus edivardsii, quite as small as Alpheus cristidigitus, were 

 found associated, also having ova attached. 



Alpheus bermudensis, n. sp. (PI. XCVIII. fig. 3). 



Rostrum short, slightly depressed anteriorly, forming a carina that extends pos- 

 teriorly as far as the orbital lobes, and separated from them by a small groove. Fronto- 

 orbital margin produced to a blunt point that reaches nearly to the extremity of the 

 rostrum. 



First pair of antennas having the first joint of the peduncle not longer than the 

 extremity of the rostrum, the second joint about the same length as the first, and 

 the third shorter than the second. The stylocerite is flat and pointed, reaching nearly 

 as far as the end of the first joint. The flagella are unequal, the upper branch being 

 about the same length as the peduncle, and the lower being about two-thirds that of the 

 whole animal. 



