ECHINODERMATA. 
563 
numerous plates of the upper surface, in the marginal plates being granulated 
only around the margin. A. insignis, sp. n., Verrill, 1. c. p. 373, pi. 4. fig. 10, 
La Paz, Lower California. 
Echinoidea. 
Cidaridoi. 
Cidaris annulosa was met with by Pourtales (/. c. p. 119) at a depth of 
270 fathoms. 
Diademidoi. 
Asthetwsoma varitmi, gen. et sp. n., Grube, 1. c. p. 44. In this genus the corona 
is flexible (4f inches in diameter, 1 inch in height). In all known sea-urchins 
calcareous particles are secreted by the skin, and these assume the form of po- 
lygonal plates. Though these plates sometimes remain very thin, yet they are 
directly applied to one another, and unite with one another to form a firm corona 
embracing the viscera. In Asthenosoma, however, the soft portion of the skin 
plays a greater part by constituting the boundaries of the larger connexions 
of the plates, or, in some cases, between each individual plate, bestowing 
thereby a remarkable flexibility, which is so great that when one places the 
sea-urchin on its edge all its orbicular body becomes crumpled up. In ge- 
neral Asthenosoma foreshadows the so-called Regtdaria in the possession of 
teeth, in the mouth being situated in the middle of the under surface, 
in the anal orifice on the dorsal surface, as well as in the arrangement of the 
feet and the disposition of the spines ; but it is noteworthy that the needle- 
shaped spines which cover all the dorsal surface, and are hollow, are covered 
by the tegument, and those on the ventral surface are very numerous and 
naked, sometimes spatula-shaped (around the mouth), sometimes of very con- 
siderable length (I of an inch), slightly bent, and becoming gradually club- 
shaped ; these latter, also hollow, are often widened out into a funnel-shape. 
The anal opening is slightly excentric and is surrounded by only four genital 
plates, of which one, the near one, bifurcates. Only three genital openings 
were found (perhaps an abnormality of the single specimen), whereas there 
are four smaller openings [ocular] between the genital plates ; the madreporic 
tubercle lies on the hinder genital plate. The pedicellaria are very numerous 
and remarkably large ; the large tubercles are distinctly pierced. The teeth 
broad on the ends and without a keel, and in form like an almost equilateral 
triangle broken at its apex. The specimen (preserved in spirit of wine) was 
of a variegated colour ; the integument was stippled with rose-red and violet j 
the spatula and club-shaped spines near the mouth are light green ; the dor- 
sal spines white, with two or three violet-coloured bauds, and the heads of 
the larger pedicellaria are greenish or brimstone-yellow. A. variumj Grube, 
Chinese Sea. 
Echinidan. 
Tripneustes ventricosus was met with by Pourtales (I c. p. 119) at a depth 
of 270 fathoms. 
Tripneustes depressns (A. Ag.)is more fully described by Verrill, 1. c. p. 375. 
It is very closely allied to T. ventricosus. 
Salmacis rttbrotinctus, sp. n., and S.festivus, sp. n., Grube, 1. c. p. 43. 
Echinus lividus. An abstract of a paper on the anatomy of this species by 
