158 



T ra ii>iitcf loiix. 



Put generally, the under arm-plates are- snicill, suL pentagonal, with 

 the proximal margin produced into an angle, intervening between the two 

 lateral arm-plates. 



The 1st under arm-plate is diamond-shaped ; the breadth is greater 

 than its length ; the sides are slightly excavated for the pedal pore. The 

 2nd and 3rd are pentagonal, broader than long. The 4th, 5th, and 6th are 

 somewhat pentagonal, but tend towards a triangle, owing to the rounding- 

 off of the sides and angles. The folloAving plates are transversely oval or 

 pentagonal, with a pronounced angle or peak proximally. The plates get 

 smaller and smaller, but do not disappear, at any rate, before the 2()th 

 joint, at which the longest arm is broken. 



The side arm-plates meet ventrally after the 5th under arm-plate, where 

 they just touch ; but beyond this point the line of union increases in extent, 

 so that soon it coincides with the length of the side arm-plate. 



Fu;. 22. 



Fjg. 21. 



()ph ill I'd /:rrniti.dccen.si,y. 



Fig. 2(1. All iiittihrachial area, seen from the side (x S). /./>., the large interbrachial 



plate : or, the oral ; 7v, marginal. 

 Fig. 21. Portion of the upper surface of an arm (x 10). 

 Fig. 22. Portion of the lower surface of an arm (x Id). 

 Fig. 2.3. Portion of an arm, seen from the side (x S). 



arm -plate. 



d, upper arm-platt 



The upper arm-plates are roughly triangular, with rounded convex 

 distal borders and with the apex directed proximally. They decrease in 

 size till about the 10th, when they disappear, or are so closely and inti- 

 mately united with the laterals that the suture is" indistinguishable. 



The side arm-plates carry 3 spines, which spring from the distal border ; 

 they are short, cylindro-conical, adpressed to the sides, and with a length 

 about one-third that of the lateral plate. Of these spines, the two lower 

 are rather closer together than the third, which is smaller than they. 



There is 1 tentacle-scale throughout the greater portion of the aim ; 

 but 2 scales to the first two pairs of pores. 



Colour. — In life Mr. Oliver describes the colour thus : " Upper surface 

 of the arms red ; the basal portion white, with a red central line ; disc 

 pink above ; 2 plates [adradials] near the arms are white edged with red ; 

 under-surface yellowish." In the dried state they are buff, with pinkish 

 tint on some of the disc-plates. 



Locality. — Dredged in 12 fathoms, on gravel bottom, off Meyer Island, 

 and in about 20 fathoms off Denham Bay (5/3/1908). He adds that they 

 are not common. 



RemarJcs. — In the small size and the fewness of the interbrachial plates, 

 with 3 arm-spines, this new species bears some resemblance to Ophioqlyplia 

 minula Lyman, but in details it differs sufficiently to entitle it to be 

 specially named. 0. minuta was obtained off the south of Australia. 



