AMBLYPNEUSTES FORMOSUS. 479 



Amblypneustes formosus 



! Amblypneustes formosus Val., 1846, Voyage Venus. 



pi viip. f. 1-2. 



Test thin, ovoid, remarkable for the distinctness and number of the median 

 sutural pores. The tuberculation is similar to that of A. ovum. The median 

 spaces of both areas are quite bare ; the secondaries of the interambulacra 

 between the principal primary vertical row are larger and more closely 

 crowded in this species, while those extending towards the median line are 

 smaller and more numerous, forming regular horizontal lines ; the rest of 

 the plate is filled by small distant miliaries irregularly scattered. As many 

 as ten or eleven tubercles in each plate in the interambulacra, and from four 

 to five in the ambulacra. There are as many as eight to ten sutural pores 

 for each plate along the median line, from which diverge, more or less paral- 

 lel to the horizontal sutures, shallow pores extending as far as the principal 

 vertical row, forming a most delicate sculpture over the median part of the 

 ambulacra! and interambulacral plates, extending from the abactinal region 

 nearly to the actinostome. The abactinal system is small ; the genital ring 

 narrow; the madreporic genital greatly larger than the other genital plates; 

 genital openings large. Poriferous zone narrow, smooth, without either sec- 

 ondaries or miliaries. Actinostome small. Spines long, slender, pink at the 

 base, frequently tipped with red or orange, or simply of a darker shade of 

 pink. The test is beautifully ornamented by dark, chocolate-colored lozenge- 

 shaped figures, upon adjoining angles of which are seated the primary vertical 

 tubercles, extending from the poriferous zone with the longer point towards 

 the median interambulacral line. Similarly shaped patches, much smaller, 

 extend from the inner part of the poriferous zone towards the median am- 

 bulacral line. Poriferous zones are yellowish, the rest of the test is of a 

 delicate brownish-pink color. Slight pits in the ocular plate as in A. pen- 



Australia ; New Zealand. 



