ON AMPHIPORUS SPECTABILIS. 281 
granular. ‘This is a conspicuous feature in the form. Dr. 
Hubrecht has not alluded to the series of apertures situated 
on each side of the sheath superiorly, and which lead—by 
channels hereafter to be mentioned—into the vascular system. 
Dr. Hubrecht says that the sheath occurred throughout 
the entire length of the Nemerteans observed by him. This 
and other remarks will not, of course, apply to the 
Carinellide. 
4, Proboscis. 
As already stated, my sole specimen of A. spectabilis on a 
former occasion did not permit me to describe or figure the 
proboscis, further than to observe that the general structure 
agreed with the typical forms; and that the longitudinal 
bands of the reticulated layer of the anterior region of the 
proboscis were especially apparent.? 
Dr. Hubrecht’s specimen has enabled me to supplement 
the hiatus to some extent, though no stylet-region is pre- 
sent. In structure the anterior region of the proboscis is 
quite typical, and though the example is everted, there is no 
difficulty in understanding all the relations by contrasting it 
with those of other species, likewise everted. Externally 
(Plate XV, fig. 1) there is the elastic layer, g, showing as 
usual towards its outer border some definitely formed fibres, 
and being often slightly granular. To judge from Dr. 
Hubrecht’s remarks he may term this layer an external cir- 
cular coat, but as longitudinal sections show only a few mus- 
cular fibres externally, the rest being nearly homogeneous 
(op. cit., Ray Society, p. 52), greater precision of descrip- 
tion is required. A glance, however, at his figures will 
decide. Within is the conspicuous belt of the external 
longitudinal muscular coat, f, which, like the other muscular 
coats, is composed of very coarse fibrils—coarser propor- 
tionally than in the largest Amphiporus pulcher in my col- 
lection, and therefore in marked contrast with the respec- 
tive appearances of the longitudinal muscular layer of the 
body-wall in the two species. This coat is followed by the 
reticulated layer, e, which is admirably shown in the Neapolitan 
form according to the interpretation formerlyladvanced (op. cit.1 
Ray Society, p. 52, &c.) The outer apices of the longitu- 
dinal bands (lozenge-shaped in such a preparation—after 
transverse section) send fibres to the outer coat of the pro- 
boscis: a few also pass towards the circular layer from the 
opposite angle. ‘The coarsely fasciculated inner longitudi- 
1 Op. cit. (Ray Society), p. 64. 
