286 llev. Thomas R. R. Stebbinc: on a 



& 



which, if present, would have held on the real spicules, and 

 have allowed the ftilse ones to be easily extracted, thus causing 

 doubt as to which spicules did and which did not reallj belong 

 to the sponge. 



At first the whiskered groups were observed to be composed 

 of spicules far too robust for the size and nature of the sponge ; 

 then it was found that their inner ends were in many instances 

 passed through the body, ahove the bottom of the cup, and then 

 that they were abruptly broken oif at their concealed or inner 

 ends instead of passing into a finely attenuated extremity. 

 Many of the robust form of spicules in the basal tuft, too, 

 were observed to be in size out of all proportion to the size and 

 nature of Laharia ; besides, a few which fell out were observed 

 to be fragments of much longer ones. Finally, by turning 

 aside a little of the basal tuft which really belongs to the sponge, 

 and which appeared to be twisted out of place, the end of the 

 tuft bound round with the fibre was discovered. 



I have thus noticed in detail this fraud in order that others 

 may not be misled by similar practices ; while they should be 

 discountenanced by those who deal with the natives for such 

 sponges, as their object is to present a saleable rather than a 

 natural specimen, and the practice will cease when they find 

 that the latter is most valued. 



XXXI. — On a Crustacean of the Genus TAsi. 

 By the Rev. Thomas R. R. Stebbing, M.A. 



The little Crustacean represented in the accompanying figure 

 I took last August in a ditch near Copthorn Common in 

 Surrey. At the first glance it presents an obvious resem- 

 blance to animals of the genus PJdloscia (Latreille), which 

 Spence Bate and Westwood, in their standard work ' The 

 British Sessile-eyed Crustacea,' make synonymous with 

 Koch's genus Zia. They introduce their description with the 

 following remarks : — " It is a curious circumstance that the 

 animals of this genus, common as they are, and well described 

 by Latreille and Zaddach, should have been unknown to 

 Brandt, Lcreboullet, and Milne-Edwards, who have affirmed 

 that the genus ought to be re-united to OniscuSj whereas it is 

 in fact more nearly allied in several respects to Ligia. The 

 typical species appears to have been figured by Koch under 

 tlie name of Ligia melanocephala, which in his generic table 

 he subsequently altered into the generic name of Zia, giving, 

 however, fifteen joints to the antennae, the flagellum being 

 represented as composed of ten articulations." 



Upon examining my little Copthorner, I found, first of all, 



