170 ECHINOIDEA. 
are rather wide. The tuberculation of the test is much more 
uniform than in many species. 
The periproct is not always longer than broad, and the hinder 
surface of the test is not straight vertically in fully grown speci- 
mens, and there may be only two pairs of poriferous plates within 
the subanal area. 
Test. Greatest diameter of 
Len eth Breadth. Hei Phe Peristome. Poriproct. 
67 65 47 15 10 
53 56 37 jal 10 
47°5 53 34 13 11 
36 40 24 et 65 
32°5 33 21°5 8:5 6 
26 26 16 6°5 +) 
Distribution. Both sides of Atlantic from Norway to Spain, and 
S. Carolina to Bahia. 
North Sea; Mediterranean. 
0-85 fms. 
a. Lamlash Bay. 
b-g. Southport. Mrs. J. E. Gray. 
h-m. Southport. Edgar A. Smith, Esq. 
n—p. Liverpool. 
q, 7. Tenby, March 1889 (low water in sand). 
s, t. Milton Sands, Devon. G. Montagu, Esq. 
u-y. Scilly Islands. 
z-b'. Plymouth. 
ce’, St. Andrews. Dr. Macdonald. 
d’-g'. Montrose. W. Duncan, Ksq. 
h'-j'. Cromarty and Moray Firths. Dr. A. Sutherland. 
k'-m'. Zetland. R. M‘Andrew, Esq. 
n’, British. Robinson Bequest. 
2. Echinocardium pennatifidum. (Plate XVI. fig. 5.) 
Echinocardium pennatifidum, Norm. Rep. Brit. Assoc. 1868, p. 315; 
Hodge, Tr. North. & Durh. iv. (1872) p. 142, pl. v. figs. 1-5; Al. 
Ag. Rev. Ech. (1872-73) pp. 111 & 351, pl. xx. figs. 1 & 2. 
Echinocardium levigaster, Al. Ag. Bull. M. C. Z. i. (1869) p. 277. 
Echinocardium sp., Bell, Ann. N. H. xvii. (1886) p. 516. 
Amphidotus gibbosus, Barrett, Ann. N. H. xix. (1857) p. 38, pl. vil. 
fig. 2 (non Ag.). 
Body less heart-shaped than in E. cordatum, being either rounder 
or longer ; anterior ambulacrum not in a groove ; spines not quite so 
silky as in Z. cordatum, but the longest in the same position as in 
it, and of much the same character both on the upper and lower 
surface. 
The test of an adult is a good deal higher posteriorly than ante- 
riorly ; the posterior end is deeply curved in its upper half and the 
periproct is overhung ; the internal fasciole is, or may be, asym- 
metrical, but the longer half may be on the right or on the left 
side ; it is some plates farther back from the madreporite than in 
E. cordatum; the number of well-marked pores is, in the first 
