NEW TYPE OF MALACOSTBACOUS CRUSTACEAN. 5 



except the terminal one, which, although of equal length to the preceding, becomes 

 rapidly attenuated, the dorsum declining in a straight line to the hase of the telson ; the 

 posterior margin is slightly excavated above the attachment of the telson, and 

 immediately lateral to that appendage it is produced to form a small acute triangular 

 tooth, at the base of which, on the inner side, there are one or two stout spines, pointing 

 upwards; lateral to the tooth the margin declines obliquely forwards along the line of 

 articulation of the uropods, to meet the inferior margin in a right angle. The inferior 

 margins of this and the preceding segment are inclined obliquely in opposite 

 directions, which allows of deeper flexion than the preceding segments. There is no 

 development of pleura. 



In male specimens there is a remarkable unpaired appendage projecting from the 

 sternum in the mid axis, and closely associated with the sexual endopodites of the 

 second pair of pleopoda. This I believe to be a development of the sternum and I will 

 describe it later when dealing with the appendages of the abdomen. 



Tlie antennules (figs. 5 & 7) are nearly half the length of the cephalon and body 

 combined: the peduncle is stoutly built and equal in length to the cephalon; it is 

 formed of three joints, the first is broad, and as lon^ as the succeeding two combined, 

 and bearing but few setse. The auditory organ is situated in this joint with the 

 opening on the upper surface, and its form appears to be quite similar to that of 

 Anaspides. The second and third joints are narrower than the first, subequal to eacli 

 other, and the inner and outer margins tufted with setae, most of which are slightly 

 feathered. The outer flagellum is slender, about twice as long as the peduncle and with 

 about twenty (more or less according to the size of the individual) short articles. The 

 secondary or inner flagellum is about one-half the length of the primary one and has 

 about eight articles. 



The antennules have the following modifications in the males (figs. 7 & 7 «)• 

 Arising from the distal extremity of the last peduncular joint, at the inner angle, there 

 is a short broad linguiform lobe with the edge evenly rounded, and fringed with long 

 curving faintly feathered setae. This lobe partly shields a remarkable pedunculated 

 eye-like organ, which projects obliquely towards the mid axis and underlies the basal 

 part of the secondary flagellum ; it arises from the distal inner angle of the first joint of 

 the primary flagellum, which is distinctly stouter than the succeeding ones. 



In shape it is somewhat like an ordinary pedunculated eye, but there is no pigment ; 

 the rounded outer surface is studded with closely packed minute hyaline hollow cups, 

 each attached to the surface by a short stalk (fig. 7 a). From a casual observation this 

 organ might easily be mistaken for an eye, but on closer examination that idea cannot 

 be accepted. I am disinclined to believe it is of sensory function, and think it more 

 likely to serve a mechanical action, such probably as clasping the female; the surface, 

 studded with its tiny hollow disks, would help in discharging this function. It, 

 however, requires more careful study by means of sections than I have so far been able 

 to give, and it may be a sense-organ. Anaspides possesses sexual modifications in the 

 males on the first seven articles of the inner flagellum, but of quite different form to 

 the above. 



