336 MB. A. V. JEXNTNGS OX THE STRTJCTFRE OF 



whole appendage seems degenerate, and the tips only are visible 

 between the tail-plate and the lamella of the first abdominal 

 appendage, its function in swimming being apparently taken on 

 by the thoracic limbs. 



IV. The Larval Stage. 



The larvae found, in the brood-chamber seem to be ail in about 

 the same stage of development, and all measure about 3 mm. in 

 length. 



They possess the subtriangular head of the adult, bearing two 

 large eyes and two pairs of antennae ; but there is no sign of 

 that antero-lateral growth of the first thoracic segment which 

 is so distinctive of the full-grown animal. 



The seven thoracic segments show little difference from one 

 another; they bear six pairs of thoracic limbs, each of seven 

 joints, and ending in a strong claw. 



In the abdominal region the segments are also at this stage 

 free ; but the large caudal plate is already well developed. The 

 last segment bears a pair of limbs, each composed of a basal 

 joint and two oval lamellsB, the outer twice as long as the inner. 

 These and the caudal plate bear strong marginal setae, and the 

 whole group, no doubt, forms a strong swimming mechanism. 



The above statement covers, I believe, all I can say as to the 

 anatomy of Ourozeuktes ; but as the genus is so little known, it 

 may be useful, for those who will some day have more material to 

 study, to summarize the previous records. 



At the commencement I have referred to the establishment of the 

 genus by Milne-Edwards and of its recognition by Gerstaecker. 

 Professor Haswell * mentions a specimen, which he calls provi- 

 sionally O. pyriformis, in the Sydney Museum, and I take this to 

 be the one collected by the ' Novara ' Expedition f- 



Messrs. Schiodte and MeinertJ add two species — the one 

 O. Monacanihi, said to be from the " body-cavity " of a Mona- 

 canthus (one of the Balistidae) preserved in the Museum at 

 Vienna; the other, O. caudatus, a badly preserved specimen 

 taken by Schomburgk near Adelaide, and now in the Berlin 

 Museum. 



* Haswell, ' Catalogue of Australian Crustacea.' Sydney, 1888. 

 t Heller, Reise der ' Novara,' Crustacea, p. 148. 

 \ Nat. TidskriCt, vol. xiv. Copenhagen, 1884. 



