S. T. Smith — Cmstaceans of the Atlantic Coast. 



75 



often have both pairs of supraorbital spines well-developed, so that 

 the two characters do not even accompany each other. This variety 

 is evidently the form of which Miers (Annals and Magazine Nat. 

 Hist., iv, XX, p. 62 (12), 1877) had a single specimen from Cape 

 Frazer, Griunell Land, and to which he refers under H. Phippsii f 



The following table exhibits these variations in a series of speci- 

 mens selected from a much larger number. In the last column I 

 have attempted to indicate the variation in the supraorbital spines, 

 although it is impossible to express in words the completeness of the 

 gradation between those individuals in which the lower spine is fully 

 developed and those in which it is entirely wanting. 



Locality. Sex. 



Grand Menan, f, 



Cashe's Ledge, 



Isles of Shoals, 

 Cashe's Ledge, 



Length. 

 24-5mm 



24-3 



25-0 



25-5 



25-2 



24-3 



21-8 



19-2 



17-0 



15-5 



18-5 



17-5 



17-1 



17-0 



16-0 



16-5 



16-7 



16-5 



15-5 



Kostrum. 

 3 + 6 



Supraorbital spines each side. 

 Two well-developed. 



Two. one very minute. 

 One only. 



One, with rudiment of 2d. 

 One only. 



u u 



Two well-developed. 

 Two, one very small. 



[ble. 

 Two, one scarcely percepti- 



One only. 



Two. 

 One. 



Li 



[ble. 

 Two, one scarcelj' percepti- 



One. 



Two well-developed. 



