434 J. J. LTSTEB. 



did not recognise the features of partionlar interest whicli 

 tliis larva presented. Having made the drawing which is here 

 reproduced (A) and a few notes, I paid no further attention 

 to it. To nay regret, I cannot now find the specimen. Although 

 the evidence in my possession is thus very imperfect, I have, 

 after some hesitation, decided to publish it, because it appears 

 to throw some light, though far from a bright one, on an 

 obscure corner of crustacean larval histoi'y. 



As may be seen from the figure, the body is enclosed in a 

 large transparent shield, produced anteriorly into a strong 

 rostral sjniie, and posteriorly into a smaller median spine. On 

 either side the lateral parts of the carapace fold round the 

 body of the larva, and where the ventral and posterior borders 

 meet, a small, backward pointing, postero-lateral spine is 

 situated. A median eye is present beneath (in a ventral view) 

 a low eminetice, and two large globular compound eyes project 

 on either side of the base of the rostral spine. Of the two pairs 

 of antennae, the first seems to have been simple, and the second 

 is biraraous, possessing a short endopodite, and a well-developed 

 swimming exopodite, jointed and beset with long setse. The 

 body appears to have been unsegmented, and the posterior part 

 is small, free from the dorsal shield, and, in the position drawn, 

 strongly flexed ventrally. It terminates in a caudal fork, the 

 divisions of which are articulated and setose. The dorsal 

 region of the posterior part of the body was tinged with red. 

 A note attached to the drawing calls attention to " rudimentary 

 appendages ^^ behind the second antennse, and states that a 

 heart was to be seen (in the position indicated) under the hinder 

 part of the carapace. There is some indication in the drawing 

 of an upper lip, between and a little behind the second antennae, 

 and the '^ rudimentary appendages" are shown to the number 

 of perhaps three, between this and the flexed posterior part of 

 the body. 



It will, I think, be admitted that the larva is in the meta- 

 nauplius stage. It seems improbable that the mandibles were 

 really rudimentary, but the mandibular palp was at any rate 

 inconspicuous, and two, perhaps, of the succeeding pairs of 



