464 ^Ir. L. A. Bonadaile on the 



liglitlj removed it to an independent division, the Stenopidea. 

 Tlie position of this group is extremely doubtfuL It has 

 clearly no relationship to the Caridea, for it differs from them 

 and agrees with the Penteidea and lower Reptantia in all 

 respects in which -the Caridea are peculiar, but its penseid and 

 reptant affinities are more evenly balanced. On the one hand, 

 like most of the Penseidea it has lost all the podobranchs 

 behind the second maxilliped and the appendices internee, and 

 has legs of the natant form ; on the other hand, like the lower 

 Keptantia, it is trichobranchiate, has a curved mandibular 

 palp and short endopodite to the first maxilliped, and lacks 

 the copulatory apparatus of the male penaiids and the spine 

 (stylocerite) on the stalk of the antennule which is so 

 characteristic of the Penseidea and Caridea. 



There would be much to be said for placing this group by 

 itself as a suborder, but, on the whole, its affinities with the 

 Natantia seem strong enough to justify its being included 

 with them. 



Since the termination -idea is used below for groups of a 

 lower rank, the names of the tribes of the Natantia have, in 

 the key which follows, been made to end in -ides. 



IV. 



AVithin the Reptantia, the Brachyura and the Anomura 

 stand out as natural groups. With these I have already 

 dealt elsewhere '^. There remain for consideration the 

 Nephropsidea, Scyllaridea, and Eryonidea. The latter two 

 of these divisions are closely related. They differ widely 

 from the Nephropsidea in the fusion of the carapace to the 

 epistome, the reduction of the rostrum f and of the inner lobes 

 of the second maxillse and first maxillipeds, the retention of 

 appendices internee on some of the limbs at least, and the 

 lack of sharp sutures on the tail-fin, and are very ancient, 

 whereas Nephropsidea, at least of the modern type, do not 

 appear till somewhat later. I propose therefore to class the 

 Scyllaridea and Eryonidea as a single tribe of the Reptantia, 

 giving to this tribe the name Palinura, which has the same 

 ending as those of the other tribes of the suborder, and recalls 

 the fact that the Palinuridse are among its members and the 

 position in which the abdomen is carried. For the sake of 

 uniformity, the Nephropsidea may take the name ASTACURA, 

 which will indicate that the tail-fin in all the members of the 

 group is like that of Astacus, one of its most common 

 representatives. Thus the old Macrura are completely 

 dispersed. 



* Gardiner's ' Fauna of the MaldiTes,' vol. ii. p. 690. 

 t Except in Palinurellus. 



