REPORT ON THE CRUSTACEA MACRURA. 



401 



developed organs, probably varying in length in different species, and the ocellus is still 

 conspicuous as a small black spot over the cerebral mass. 



The first pair of antennae consists of four joints, of which the first is very long, 

 nearly equal in length to the carapace, the second and third are short and subcqual, 

 while the fourth is but a rudimentary bud ; from the inner surface of the inner distal 

 angle of each joint there springs one small hair, and the rest of the appendage is 

 smooth. 



The second pair of antennae is long, apparently longer than is represented in the 

 drawing, which is shortened, and the first pair is bent, probably in order to bring the 

 drawing within the limits of the paper used ; the flagellum is multiarticulate, the articuli 

 being long aud slender, the first or basal being alone furnished with one small hah' ; the 

 scaphocerite is long and narrow, with the margins parallel, the inner being fringed w T ith 

 a few separate small hairs or cilia, and the outer produced to a tooth-like point at the 

 distal extremity. With this antenna is connected an internal organ, which is known as 

 the green gland ; it consists of a long, tubular ramification folded within a compressed 

 compass smaller than its length. The length of the antennal somite, measured from the 



Fig. 65.— Mandible. 



Fig. 66.— First maxilla. 



anterior margin of the cephalon to the oral apparatus, ecrnals that of the pereion 

 measured from the anterior surface of the labrum to the posterior extremity of the 

 carapace. The diameter of the animal, viewed dorsally, is greatest across the line of the 

 mandibles, from which point the pereion gradually and rapidly narrows until at the 

 posterior extremity it is of the same width as the narrow, compressed somites of the 

 pleon. The epistoma differs from that of the previous specimens in having the tooth, 

 which is a prominent feature in those, reduced to a small lobe. 



According to the drawings of Willemoes Suhm, as shown in the adjoining cuts, the 

 oral appendages are approximating to those of the adult, and may be compared with 

 those given on PI. LXXIX. 



The mandibles have the incisive margins serrate, but not uniformly or symmetrically, 

 the one being more deeply toothed than the other. 



The first pair of siagnopoda or maxillae is two-lobed, the distal lobe being the broader, 

 and fringed on the inner margins with a series of simple spine-bke hairs, set thickly 

 together, and the basal lobe is narrow and furnished with three serrate and one simple 

 spinedike hairs, and on the posterior margin is a long blunt styliforrn process. 



