TPIE OPIIIURIDiE. 



133 



*j- 



broad, more hexagonal). The following plates are about equally broad and 

 long; all with an angle within and outer edge cin^ved. Second to fourth 

 have outer laterals re-enteringly curved on account of the tentacle pores ; 

 from the sixth they are triangular, with all the sides a little curved. They 

 continue almost to the end of the arm, sometimes only to about the 30th 

 joint I they are all widely separated by the side arm-plates ; in some of the 

 larger specimens, however, the second to fifth may be in contact, the inner 

 end of these plates being then truncated. First and second ventral plates are 

 very seldom in contact. Side arm-plates somewhat rounded, outer edge a 

 little prominent} they meet above from about the sixth (free) joint. The 

 dorsal plates are as long as broad, almost rliomboidal on the inner joints, 

 with an angle within and without; farther out they become more elon- 

 gated, with an acute angle within and an obtuse angle without. They 

 are distinct almost to the end of the arm. The second dorsal plate has its 

 inner angle truncated ; in some specimens that is the case with others of _ 

 the inner dorsal plates. The first is creScent-shaped, broader than long ; 

 inside this there are 3-4 short, broad, irregular, rudimentary dorsal plates. 



Disk covered with small, usually angular scales, among which the pri- 

 mary plates are hardly distinguishable. Radial shields very large, widely 

 separated by several irregularly placed scales. One rather large, semi- 

 lunar marginal plate in the interbrachial space. Ventral side of the disk 

 covered with similar polygonal scales, among which are sometimes seen 

 some small spines or grains. Towards the margin there are some few larger 



f 



scales. Edge of the disk rather sharp, the dorsal side not rounding towards 



+ 



the ventral side. Genital scale narrow, but usually distinct in the whole 

 length. Genital slits reaching only the third joint, with a double row of 

 close set, square papilla), one on the genital scale, the other along the side 

 arm-plates. Outside the genital slits the genital scale widens and bends a 

 little away from the arm ; for which reason the third and fourth arm-joint 

 appear somewhat wider than the other arm-joints. (Not always so distinct 



as in Figure 7.) 



Seven to eleven short, delicate arm-spines, equally spaced. Only the 

 lowest one is sometimes thicker and longer than the rest. Four pairs of 

 large tentacle pores; some specimens have five pairs; not seldom only one 

 of the pores of the last pair is developed. One rather large tentacle scale 

 on the outer side, and one or two on the inner side. 



y^- 



Color in alcohol : gray. 



6 



^ 



f- . 



