155 
Fig. 7. Apical system of 
Notechinus novæ-zealandiæ 
The periproct slightly re- 
constructed, (the part off 
Ocular I.) Vi¬ 
oles of the primary tubercles are confluent on the oral side, but 
not above the ambitus, even in the larger specimens. The second- 
ary tubercles are generally rather large, almost as large as the 
primary ones; they form, inside the primary series, one very dis 
tinet, nearly complete series, and, at the ambitus, a second se¬ 
ries, shorter or longer, according to the size 
of the specimen. Outside the primary tub- 
ercle there are at the ambitus in the larger 
specimens one or two transverse series con- 
sisting each of two larger secondary tub¬ 
ercles, plates with one or two such series 
alternating more or less regularly. These 
outer secondary tubercles do not form very 
regular vertical series. On the plates with 
only one series of outer secondary tubercles 
the primary and secondary tubercles together 
form a very distinet horizontal series through- 
out the whole breadth of the plate; in those 
plates which have a double series of outer tubercles the transverse 
series is less regular. The interambulacral areas upon the whole 
are very closely covered by the tubercles, no naked median space 
being left. 
The apical system (Fig. 7) is remarkable through its small size, 
occupying, in the larger specimens, scarcely more than l / 6 °f the 
h. d. The genital and ocular plates are generally closely tubercul- 
ated; Ocular I is insert. The madreporite is distinetly elevated. 
The periproct is somewhat oblong, the anal opening being excent- 
rical, situated more or less close to the edge, off Oc. I; there is a 
more or less complete circle of outer, larger plates, the one oppo- 
site the anal opening (adjoining Genital III), representing the anal 
plate, being somewhat larger than the rest. They are all thick and 
somewhat elevated, all perfectly naked. Inside the outer circle are 
some small, generally somewhat elongated plates, surrounding the 
anal opening. In the largest specimen some smaller plates have 
appeared outside the circle of larger plates, the anal plate thus 
being separated from the edge of the periproct. 
