72 THE LINGULIDZ OF THE QUEENSLAND COAST. 
but the general disposition of the patches is constant. 
Morse believed the arrangement to be of specific value. We 
agree with his suggestion (p. 349) that these areas are prob- 
ably sensitive to light. They are restricted to those portions 
of the pallium lying in the translucent region of the shell 
which can be projected above the surface of the sand. 
The peduncle is highly contractile (text-figure 2). In 
life the centre is creamy in colour but has a tinge of pink 
after preservation. The horny envelope is quite trans- 
parent. The whole peduncle and also its inner muscular 
portion gradually become narrowed as they pass back from 
the insertion into the ventral valve, being narrowest just in 
front of the ampulla where the stalk widens as a*thin walled 
organ. The horny layer of the anterior part of the ampulla 
is considerable thickened. Surrounding the ampulla is a 
tube of agglutinated sand grains. The structure of the 
peduncle is like that described by Gratiolet (1860, pp. 63- 
70) and King (1873, p. 14). 
The arrangement of the sete resembles that in L. 
anatina (Morse pl. 40, fig. 16 ; Francois 1891, 1895, fig. 315), 
the median and anterior clusters projecting freely, the 
lateral setze only slightly, while the posterior cluster is very 
distinct on each side. Rather long setze surround the base 
of the peduncle. The anterior lateral setz are very long 
in young specimens (text-figure 1), measuring as much as 
3.5 mm.inaform12mm.long. In the lateral and posterior 
setze which are doubtless the organs by which Lingula 
climbs up its tube, one notices a strongly marked alter- 
nation of brown and colour‘ess regions, particularly in the 
basal portion of each seta. 
In L. bancroftt the pallial sinuses resemble those 
figured by Hancock* (pl. 64, fig. 3) for L. anatena except 
that there is commonly a certain amount of branching of 
the most anterior channels and, at times, of some of the 
laterals also. Gratiolet published figures (pl. 7, fig. 1; 
p. 89. fig. 15) showing occasional branching of the anterior 
pallial sinuses in LD. anatina, such a condition being also’ 
indicated in one of his figures of L. hians (pl. 9 fig. 1). In 
L. affinis the sinuses are few and branch in a marked manner 
*Hancock’s L. anatina is not L. anatina Lam. but L. murphiana. 
