PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 7 



It raay be distinguisbed from tbe commou species of our coast, Belonc 

 longirostris, (Mitcbill) Gill, by many characters, tbe most salient of 

 which are the more elongate form, the lesser proportionate length of 

 the head, the much greater number of rays in the vertical fins {B. (ati- 

 manus has D. 25: A. 23. B. longirostris has D. 13-1(3 : A, lG-19), tbe 

 broader and proportionately shorter pectorals, and the forked caudal. 



The length of the specimen was 49 inches (1244.G millimetres), its 

 weight 5J pounds (2381 grams). 



Color: — Back, top of bead, and snout dark green in dead specimen, 

 probably beryl-green in life. Fin-rays greenish-brown. Fin membranes 

 and protected parts, such as axils of pectoral fins, colorless. Sides light 

 brownish, with silvery overwasb. Belly, cheeks, throat, and lower part 

 of lower jaw silvery-white. Eye greenish-yellow. 



Badial /orwmZa.— Brancbiostegals XIV. D. 24: A. 25: C. 7-6+7-5: 

 P. 12 : V. 6. 



January 15, 1878. 



TIBSE VOICES OF CKIISTACEANS. 



By €i. BROIIVN «001>£. 



The observations of Mr. Saville Kent and Mr. J. Wood Mason (Na- 

 TURE, vols, xvi, p. 565, and xvii, p. 11) recall to mind some similar 

 facts recently noted by me in tbe Bermudas. 



Several species of Alpheus were observed to have the power of pro- 

 ducing loud clicking sounds. Two or three of the larger species are 

 accustomed to lurk under flat stones near low-water mark. Some of 

 these are two inches long. When one of them is taken between tbe 

 fingers by an inexperienced collector, tbe sudden, convulsive snap 

 almost invariably causes him to drop it. Tbe effect is like that of a 

 sharp blow across the knuckles. Some smaller species of the genus 

 are found only in the cavities of a large aplysine sponge, abundant on 

 tbe reefs. I have picked out seventy or eighty from a fragment of 

 sponge not more than three inches in diameter. When the sponge is 

 taken in the band, tbe quick succession of clickings reminds one of the 

 sound of instruments in a large telegraph office. When one of these 

 animals is put in an earthen or glass vessel, it makes a much louder 

 noise, resembling a quick tap with the finger-nail or tbe back of a knife 

 upon tbe edge of the same vessel. This noise is produced by a convul- 

 sive snapping of tbe last joint of tbe large claw, by a movement resem- 

 bling that of tbe spring beetles {E later idee) ^ and tbe sounds are quite 

 similar. Possibly these movements may have a protective object, enab- 

 ling tbe little decapods to escape from the grasp of enemies, or to work 

 out from under the stones and loose sand in which they must often 

 become buried. 



Another macrurous crustacean, Gonodactylus cJiiragra, known to the 



