LYTECHINUS VERRUCULATUS. 253 



This pretty little species was collected by the "Blake" in the West Indian 

 region, but many of the specimens were not distinguished from Genocidaris 

 maculata, a species with which they were often taken and from which they are 

 not easily distinguished, unless the specimens are dry. The coloration is very 

 distinctive even though variable, while the small number of ambulacral plates 

 as compared with the interambulacral is quite remarkable. The relationship 

 of this species to both euerces and variegatus is obvious, but it cannot be confused 

 with either. It was taken by the "Blake" only in the vicinity of Dominica, 

 Grenada, and Barbados, in 69 to 170 fathoms of water. Of the seventeen 

 specimens at hand twelve are from Barbados, 



Lytechinus verruculatus, comb. nov. 



Psammechinus verruculatus Llitken, 1864. Vid. Med., p. 166. 



It seems probable that Mortensen is right in associating this species with 

 variegatus. Although none of the specimens before me are nearly so large as 

 those which de Loriol had from Mauritius, there seems to be no doubt of their 

 identity. The "Albatross" specimens reveal the same peculiarities of coloration 

 described by Mortensen (1904, Siam Ech., p. 123). In the smallest specimen 

 the rings on the spines are red and the same color appears on small spines of 

 larger specimens. Many primaries are red at base while in a few specimens, 

 the base of the primaries is violet. There is great diversity in the depth of the 

 colors marking the test. Although all the "Albatross" specimens are immature 

 ranging only from 5 to 12 mm. in diameter, the seven examined in regard to the 

 ocular plates showed the adult character nearly acquired. For five have 

 ocular I broadly insert, and in three specimens, V also is almost in. Of the 

 other two specimens one is a very rare variant, with only ocular IV insert and 

 the other is a much more interesting variant with I and II insert as in Gym- 

 nechinus; the periproct is not however excentric. 



Station 3847. Off Lae-o Ka Laau Light, Molokai, Hawaiian Islands. Bott. 

 temp.? 23-24 fathoms. S., st. 



Station 3871. Off Mokuhooniki Islet, Molokai, H. I. Bott. temp.? 13-43 

 fathoms. Fne. wh. s. 



Station 3872. Off Mokuhooniki Islet, Molokai, H. I. Bott. temp. 74.6. 

 32-43 fathoms. Yl. s., p., co. 



Station 3955. Off Laysan Island, H. I. Bott. temp. 74. 20-30 fathoms. 

 Co., r., alg. 



