EEPORT ON THE CRUSTACEA MACRURA. ' 91 



mine, on any of the others. The pleon is short and without any evidence of possessing 

 appendages. 



The specimen next in size is from the Celebes Sea (PL XIIa. fig. 3) and is 7 mm. in 

 length. That is, it has increased in dimensions about five times without any very great 

 variation in form or growth of parts, and as there is in the development of separate 

 species of the same genus and generally in different genera of the same family the same 

 structural characters, I shall consider the several specimens taken as being successive 

 stages in their relation to each other. The ocellus is still very distinct, and the 

 ophthalmopoda have increased in length considerably and become Inarticulate, one 

 articulation at the base and the second at the root of the ophthalmus, which is long and 

 pear-shaped. The first pair of antennae is biarticulate but not biramose. The secpnd 

 shows evidence of becoming so, but not very conspicuously ; at its base a series of 

 cells are arranged in the form of a circle, and behind this the green gland appears 

 in an incipient stage. The hepatic lobes, w T hich in the previous stages were large and 

 few, are here increased in number and arranged in a series of ceeca symmetrically 

 disposed on each side of the carapace, and which empty themselves into a longitudinal 

 duct that is united with the main viscera near the stomach and above the oral ajjparatus. 



The mandibles are distinctly visible, sharp-pointed, and enclosed between the 

 cheiloglossa and the metastoma or posterior lip, behind which, and clasping it closely, 

 the first pair of siagnopoda is visible, in form somewhat resembling that of the adult. 

 The distance from this latter organ to the anterior margin of the pereion is considerable, 

 corresponding as this does with the posterior margin of the cephalon. At the anterior 

 angle of the pereion is a pair of biarticulate appendages, short and rudimentary, the 

 second joint being shorter than the first. Near this is a second small but well-developed 

 pair of unbranched five-jointed limbs, a few hairs existing on the two terminal joints ; 

 this is the first pair of gnathopoda. The next and three following pairs resemble each 

 other; they are biramose, rather longer than the animal, seven -jointed and carry a 

 long basecphysis. The next succeeding, or seventh pair of appendages is short and 

 feeble, being in an immature condition ; it is four-jointed and carries a small basecphysis. 

 Posterior to this pair and situated in the angle formed by the union of the pleon with 

 the pereion there is a small vesicle, the germ of another pair of appendages. The pleon 

 is small and without any evidence of the future appendages. 



The next specimen, and one which has the appearance of being the young of the 

 same or a closely allied species, is from the West Pacific, and is about 14 mm., or double 

 the length of the preceding (PI. XIIb. figs. 1-3). 



The central eye has become reduced in size. The ophthalmopoda are two-jointed. 



The first pair of antennae has become four-jointed and biramose, the smaller branch 

 springing from the distal extremity of the third joint. The second pair of antennas is five- 

 jointed and exhibits on the metope or ventral surface near the base of the antennae a 



