14 Rev, T. R. R. Stebbing on AmpMpodous Crustacea. 



would prove to be the case. I first took the female at Anstis 

 Cove, Torquay, on the 21st of March last, under a stone at 

 extreme low-Avater mark, in company with Janira maculosa. 

 Since then I have taken both forms in companionship, and 

 again, along with Janira maculosa ^ under similar circumstances 

 in Salcombe Harbour. They have probably often been seen 

 before, but mistaken for the young of the everywhere abundant 

 Gammarus locusta. The shortness of the tail is an obvious 

 distinction ; but, as the creature when alive keeps it for the 

 most part curled under its body, it is not such a telltale as 

 it might otherwise be. 



The difference in the length of the flagellum of the superior 

 antennae, noted by Bate and Westwood as one of the chief 

 distinctions, was merely an accidental variation in their speci- 

 mens. The length of this appendage undoubtedly varies in 

 both forms, as it does in many other species of sessile-eyed 

 crustaceans — so as to make it a very unsafe character on which 

 to ground a specific difference, unless a large number of indi- 

 viduals have been examined and found constant in this 

 feature*. 



The only difference of importance between the two forms 

 is in the second pair of gnathopoda. In the male the hand is 

 very large, long, and oval, with a short cup-shaped wrist, and 

 having the palm fringed with ten or a dozen thorn-like bristles, 

 along the inner side of which lies the strong and long finger, 

 tapering almost to the extremity of the palm. The length of 

 the finger, however, is somewhat variable. The corresjjonding 

 pair of legs in the female have the wrist and hand long and 

 nan-ow, slightly pubescent, of nearly the same length and 

 breadth, and terminating in an inconspicuous finger. The 

 first pair of legs are very similar to the second, but have the 

 hand shorter than the wrist ; they do not seem to differ at 

 all from the first pair of legs of the male. 



The coxas of the first three pairs of legs have a small tooth 

 at the postero-inferior margin, not particularly easy to observe. 

 The thighs of the last three paii-s, and especially of the last 

 pair, are seiTated in a very conspicuous manner : those of the 

 last pair differ slightly in the male and female — the male 

 having the posterior margin almost in a single curve, with a 



• * Thus in Ampelisca carinata, Bruzelius {Ampelisca Gaimardii of Bate 



and Westwood), the inferior antennae are stated by the latter authors to 

 be two thirds the length of the animal : and so they sometimes are ; but 

 Mr. Norman speaks of the Scotch specimens as having the inferior an- 

 tennas " extremely long, equalling the whole length of the animal," and 

 I have two fine specimens from Salcombe in which they are longer than 

 the animal. 





