1863.] ON NEW AUSTRALIAN CRUSTACEA. 503 



thopoda are pediform. The first pair of pereiopoda are chelate, 

 slender, the propodos being slightly enlarged, and the dactylos straight 

 and nearly as long as the propodos. The second pair of pereiopoda 

 are longer than the first, and also larger ; the dactylos is slightly 

 longer than the antagonizing process of the propodos, but not longer 

 than the propodos independently of the dactyloid process. The 

 posterior three pairs of pereiopoda are about the same length as the 

 first, but more slender, and have the propodi armed with a few short 

 spines. The posterior pair of pleopoda are slightly longer than the 

 telson. Telson obtuse at the apex, and furnished with two long and 

 four short spines. 



This species has not had the colour observed when alive ; but in 

 a preserved condition it is yellowish, mottled with red, especially upon 

 the pereiopoda, antennae, and rostrum. It was taken, with the pre- 

 ceding species, in Gulf St. Vincent. 



In this species there are two remarkable and interesting peculiari- 

 ties existing in the superior antennae. The one is, that at the base 

 of each appears an appendage very like a true otolithe. In Dana's 

 figure of A. ensifrons, the organ that he has drawn in the same po- 

 sition, I have little doubt, demonstrates the presence of the same. 

 This is so unusual that I know of no other species with such a struc- 

 ture, except it be a Stomapod spoken of by Huxley. This organ 

 bears a near resemblance to that which Van Beneden considers to be 

 an otolithe, and which was found by him in the inner ramus of the 

 posterior pair of pleopoda in some species of Stomapoda. The second 

 peculiarity in the condition of the superior antennae is the fusion of 

 the primary with the secondary appendage through nearly the entire 

 length of the former — and this not by an absorption of the one into 

 the other, but by an apparent union of the two along their margins. 

 This condition exists occasionally more or less in other genera. 



Crangon. 



Crangon intermedius. (PI. XLI. fig. 6.) 



C. tres denies supra regionem hranchialem anteriorem et ordinem 

 parvulorutn dentium post externum dentem orbitcR habens. 



Having the carapace armed with three teeth on the antero-bran- 

 chial surface on each side, and a row of minute denticles extending 

 from the extraorbital tooth posteriorly between the cardiac and 

 branchial regions. The rostrum is nearly as long as the eye. The 

 superior antennae are three times as long as the eye, having the rami 

 subequal and as long as the peduncle. The inferior antennae have the 

 squamiform appendage reaching nearly to the extremity of the supe- 

 rior antennae. The first pair of pereiopoda are subchelate, strong, 

 having the palm oblique, marginate, and armed with alternating long 

 and short hairs. The second pair of pereiopoda are chelate, slender, 

 and do not reach beyond the carpus of the first. The third pair of pe- 

 reiopoda are slender and longer than the first ; the remaining two 

 pairs are shorter, being but a little longer than the second. The pleon 

 is short, being scarcely longer than the carapace, and suddenly narrow- 



