Mr. L. Barrett on new species of Echinodermata. 47 



plates. The ambulacral grooves are partly concealed by two rows 

 of small bundles of long spines. The triangular spaces between 

 the ambulacra and the margin are covered by numerous oblong 

 tubercles, which bear numerous spines, similar to those which 

 cover the marginal plates. We have dedicated this species to 

 M. Lutken of Copenhagen, who has described many of the 

 northern Echinodermata. 



Common in deep water off the coasts of Nordland and Fin- 

 mark. 



Astrogonium aculeatum. PL IV. fig. 4 a, b. 



Specific character. — Disk pentagonal; rays somewhat pro- 

 duced; each side made up of two rows of eight intermediate 

 lateral plates, which are largest at the junction of two rays ; the 

 upper surface of these plates is naked, but on the sides and 

 under surface they bear numerous unequal granules ; those on 

 the sides are largest at the apex of the ray, and form two rows ; 

 those on the under surface are small, and are placed in a single 

 row around the margins of the plates. The upper surface be- 

 tween the lateral plates is formed of numerous nearly circular 

 plates, each of which is surrounded by a circle of globular gra- 

 nules. Ambulacra protected by two rows of long and two rows 

 of short spines. The other part of the under surface is com- 

 posed of rows of oblong plates, each of which bears about six 

 globular granules. 



Only one specimen was dredged in 100 fathoms water off the 

 coast of Finmark. 



Astrogonium boreale. PL IV. fig. 5 a, b. 



Specific character. — Disk pentagonal, bordered by two rows 

 of large marginal plates ; each side is made up of two rows of 

 eight intermediate lateral plates. Apex of the ray formed of a 

 single triangular plate; the exterior edges of lateral plates 

 covered with compressed granules. The upper surface of the 

 disk composed of numerous hexagonal plates covered by com- 

 pressed granules, except those near the centre, which bear gra- 

 nules only on their margins ; near the middle of the disk are five 

 smooth plates arranged in a circle round the centre. The mar- 

 ginal plates, on their under surface, have a single row of small 

 granules round their margins. The ambulacral groove is bor- 

 dered by two rows of long and four rows of short spines; the 

 other part of the under surface is covered with numerous plates 

 bearing granules. 



One specimen occurred off the coast of Finmark in 150 fms. 

 water. 



