286 Mr. Westwood on Diopsis, 



To these may be added, from the Brachyurous family, Ocypodidce, Westw., 

 or Crabes quadrilateres of Latreille ; the Biitish genus Gonoplax, Cancer an- 

 gulatus, Linn. ; the American genus Gelasimus, and the New Holland one of 

 Macroj>hthalmus,hatv. {RegneAnim., 2nd edit., vol.iv. p. 44.) ; in all of which the 

 footstalks are disproportionately long : but the greatest elongation in the Bra- 

 chyitra takes place in tlie genus Podophthalmus, Latr. {Portunus f igll, Fab., Isle 

 of France), belonging to the family Canceridce,Westw. {Crabes nageurs, Latr.). 



The order Macrura does not present any remarkable development in the 

 length of the ocular peduncles in any species with which I am acquainted ; 

 but in the next order, Stomapoda* , two tropical genera, Luc'ifer and Podopsis, 

 have recently been described and figured by Mr. Thompson in his "Zoological 

 Researches," remarkable not only for the great length of the peduncles, but 

 also for the attenuated vermiform shape of their bodies and their luminous 

 properties. To these I have added another, nearly allied, with equally long 

 footstalks, under the name of Stylophthahna, founded upon a curious species 

 figured by Slabber. The only instance which occurs of pedunculated moveable 

 eyes in the great Crustaceous division of Entomostraca, is found in the three 

 genera forming the order Branchiopoda. In the class Arachnlda I have recently 

 characterized a spider from Malabar under the name of Phoroncldia acideata, in 

 which the front of the cephalothorax is produced in front into a thick footstalk, 

 at the extremity of which the eight eyes are placed (Zool. Journ. No. 20.). It is 

 nearly allied to the cancriform Epeirce-\-. {Acrosoma, Perty,Dil. An., art. Braz.) 



This representative structure, moreover, is not confined to annulose animals, 

 since it exists in other remote groups, and even amongst the higher animals, 

 as though, amongst the Vertebrata, — to use the language of a fanciful Ger- 

 man author, — the Squalus Zygcena of Linnaeus had shot through the waves 

 and landed in Java or Brazil, transformed into a Dipterous insect ; whilst 

 everybody is aware that amongst the Testacea the eyes of the Snails are 

 placed at the extremity of long retractile footstalks. 



* The number of remarkable and analogical forms contained in this group appears to me to be con- 

 clusive evidence of its rank as an order, although Mr. MacLeay, foUowing Dr. Leach, is of a different 

 opinion. 



t The Epeira curvicauda of Vauthier, described in the Annates des Sciences Nalurelles, has the two 

 lateral eyes on each side placed at the extremity of a short common footstalk. 



