148 Miscellaneous. 



the mandibles are stout cutting-blades, with no trace of a palpus, or 

 of the swimming-branches of the appendage. The first maxilla is 

 small and jaw-like, while the second is long and slender, with a very 

 small scaphognathite. There are three pairs of maxillipeds, all of them 

 biramous. The first pair are large, fringed with long swimming- 

 hairs, and they are efficient swimming-organs. The second pair 

 are much smaller and of less functional importance ; and the third 

 pair are rudimentary and scarcely visible. The long slender hind 

 body shows only very faint traces of a division into segments ; and 

 no ganglia could be made out. The tip of the abdomen forms a 

 forked telson, with seven pairs of plumose hairs — one short one on the 

 inside edge, another short one on the outside edge, and a terminal 

 row of five much longer ones, the middle one being the longest 

 of all. 



After moulting, the "second Protozoea" is essentially like the 

 first, the chief differences being that the compound eyes are now 

 movable, and the hind body is sharply divided into segments. No 

 joint as yet separates the telson from the sixth abdominal segment ; 

 but, with this exception, all the segments of the hind body are now 

 well defined. 



In the species which was studied, probably Penceus brasiliensis, 

 the rudimentary thoracic and abdominal appendages described by 

 Claus at this stage were not visible. I did, however, find a few 

 specimens of another species which agreed in this respect with 

 Clauses figure. 



After the next moult the larva becomes what I have called in 

 my paper on Lucifer a " Protozoea with preparations for the 

 Schizopod stage." 



It might, perhaps, be spoken of as a Zoea. The ocellus is still 

 present, although the compound eyes are large and quite movable. 



The rostrum is lengthened. The two pairs of antennae retain the 

 Nauplius characteristics. 



The mandible has no trace of a palpus ; and the metastoma con- 

 sists of a pair of broad flat plates, separated from each other on 

 the middle line, and placed in the same series with the other 

 appendages. 



The maxillae and maxillipeds are as they were at the stage before, 

 except that the third pair of maxillipeds are a little larger although 

 they are still rudimentary. 



The five thoracic somites are now cemented together ; and each 

 bears a pair of buds or pouches, the rudimentary appendages 



The telson is separated by a joint from the sixth abdominal seg- 

 ment ; and the latter carries a pair of rudimentary swimmerets. 

 There are no traces of appendages on any of the other abdo- 

 minal segments, although all the ganglia are conspicuous and 

 well developed. The halves of the fork of the telson diverge from 

 each other a little more than they did during the earlier Protozoean 

 stages. 



After the next moult the animal reaches the Schizopod stage, so 

 far as the anterior half of the body is concerned, although the abdo- 



