398 PERCY SLADEN TRUST EXPEDITION 



to it, showing that we have here quite possibly a number of distinct local races — 

 a rare phenomenon among Oarides. Nihoides maldivensis is a second representative of 

 a genus which has not been met with since it was described in Paulson's well-known but 

 for a long time inaccessible paper on the Decapoda of the Red Sea. Lastly, a study 

 of the species of Amphipalcemon, Hymenocera, and Gnathophyllum has elucidated the 

 relationships of these very interesting and remarkable genera, and necessitated a very 

 considerable rean-angement of families in the neighbourhood of the Crangenoida. There 

 is, indeed, no exaggeration in saying that the result of the examination of this little 

 collection will be to bring about fundamental alterations in our ideas of the affinities 

 of the higher families of the Carides. 



It is unfortunately not possible at present to draw any conclusions concerning the 

 geographical distribution of the Indopacific prawns. 



The following is a list of the species, with comments upon facts of interest 

 concerning them. 



Superfamily Pasiph^oida. 



Family Pasiph^id^. 



Genus Leptochela. 



1. Leptochela robusta Stimpson, 1860. 



Proc. Acad. Philadelphia, 1860, p. 43. de Man, Abh. Senckenb. Ges. xxv. iii. 

 p. 902 (1902). 



Haddumati Atoll, Maldive Is. 



Superfamily Pandaloida 



Family Pandalidje. 



Subfamily Pandalin^. 



Genus Pandalus. 

 Subgenus Plesionika. 



2. Pandalus (Plesionika) gracilis Borradaile, 1915 (Plate 58, fig. 1). 



Ann. Mag. Nat. Hist. (8), xv. p. 208. 



Diagnosis : The rostrum is long (its tip appears to be damaged in the specimen) 

 and of even width throughout. At its base two strong teeth stand above the eye on 

 a crest which extends backwards over the first half of the carapace. The rostrum itself 

 is gently upcurved from the base ; about the hindermost third of its length is unarmed; 

 the rest bears below a series of small sharp teeth, set wider apart towards the tip 

 of the organ, and above eight minute spinules, widely set, the last two being some- 

 what larger than the rest. The eye is wider than its stalk, and has a distinct ocellus. 

 The stalk of the antennule is less than the length of the antennal scale. The flagella 



