108 MR. W. K. BROOKS OX LUCIFER: 



the first antenna, including the flagellum. Its inner end carries eight, and its tip 

 three hairs, and the outer edge of the tip is toothed. The swollen base of the flagellum 

 of the second antenna carries a large red pigment-spot, and the flagellum, which is 

 considerably longer than the body of the animal, is also marked by bright-red pigment 

 throughout the greater part of its length. 



The second maxilliped has become completely bent upon itself, and it bears a close 

 resemblance to that of the adult Lucifer, although it carries a gill, as do the second 

 maxillipeds and the three pairs of thoracic limbs. All traces of the exopodites have 

 disappeared from all these appendages, but their structure and comparative length are 

 about as before. 



The first, second, and third pairs of abdominal feet have increased in length, and 

 the first is now almost as long as the last thoracic limb. The second is a little shorter ; 

 the third is still shorter, and has acquired a second terminal branch, which is as yet 

 rudimentary. 



The fourth and fifth pleopods, which have now made their appearance, are much 

 smaller than the others, and each has one large and one small terminal branch. 



The swimmerets and telson are very similar to those of the immature Lucifer, 

 although the telson is shorter and wider. The exopodite has fifteen hairs on its 

 inner edge, two on its rounded tip, and four between the tip and the tooth. The 

 endopodite has nineteen hairs. The surface of the carapace is finely punctated, and 

 the rostrum has no secondary spine. The spine has disappeared from the first 

 abdominal somite, and the one on the third somite is longer than any of the others. 

 The dorsal surface of the third somite is bent, so that the abdomen is no longer per- 

 fectly straight. Large conspicuous red pigment-spots have appeared on the lower 

 edges of the second, third, fourth, and fifth abdominal somites. 



As the series of drawings which I have given was made from such a small number 

 of specimens, I am unable to contribute much information as to the changes of the 

 mouth parts, and must leave this, as well as the exact determination of the adult form 

 and systematic position of the species, to future research. 



In his ' Facts for Darwin ' FR. MULLER has figured a larva (fig. 33) which is 

 extremely like, if not identical with the one shown in fig. 90, and he regards it as the 

 young of a Prawn, closely related to Penceus. GLAUS has suggested (' Crustacean- 

 System,' p. 35) that it is much more likely to prove to be a young Sergestid than a 

 Prawn, and the facts regarding its metamorphosis which T have given above, certainly 

 seem to point in the same direction. An earlier stage of development is given in 

 FR. MULLER'S fig. 32, and a comparison with my fig. 84 will show that the same larva 

 at an earlier stage might, when crushed by a cover glass, present very much the same 

 appearance as this larva. If they are the same FR, MULLER is certainly mistaken in 

 his statement that fig. 33 follows directly after fig. 32, without the intervention of a 

 Schizopocl stage, for the metamorphosis is really quite complicated, and a true Schizopod 

 stage exists, although it is of extremely short duration. 



