166 ANTHURID^E. 



five basal segments of the tail, the smooth surface of 

 the middle tail-piece, oval at its extremity, the very 

 distinct and oval terminal division of the inner plate of 

 the side appendage of the tail, and the smaller and 

 narrower size of the outer division. The hand of the 

 fore pair of legs also wants the notch along its under 

 edge. It is of a pale bone colour, covered with minute 

 black dots. The mouth is enclosed between horny 

 plates (f) and furnished with a pair of straight, elon- 

 gate-conic mandibles, pointed at the tip, having a large, 

 three -join ted, palpiform appendage fixed at its base on 

 the inner edge. The maxillae consist of a pair of long, 

 very slender, slightly curved, lancet-like pieces, retro- 

 serrated at the apex, and the mouth is closed beneath 

 by a broad pair of foot-jaws, which are terminated by 

 two large, flat joints, the apical one being strongly 

 ciliated. 



In all these particulars it perfectly agrees with other 

 specimens preserved in spirits in the same collection, 

 with a label inscribed " Anthura gracilis," in the hand- 

 writing of Signor Costa, of Naples, with whom Mr. 

 Hope was long in friendly communication upon the 

 marine animals of the Mediterranean. On referring to 

 Mr. Hope's catalogue of the Mediterranean Crustacea, 

 we find only one species of Anthura indicated with the 

 name of A. gracilis , which, from a copy marked by S. 

 Costa, we find to be in his collection ; and we have, 

 therefore, no doubt that the species was communicated 

 by him to Mr. Hope. We therefore at first hesitated 

 to consider the species as a real native of this country 

 (fearing some confusion might have occurred as to the 

 labels of the South Western Coast specimens), and, in 

 honour to Signor Costa, we proposed for the species the 

 name of Paranthura Costana. Whilst, however, this 



