142 LANICE CONCHILEGA. 



(Plate CXXVa, figs. 4, 4 a 9 4 b) are bound firmly together in flattened fascicles, slope 

 outward or obliquely upward and outward, and have a pale golden hue. They have 

 a pale base, a shaft with fine striae internally, and a tapering tip with a double wing, 

 the latter being obliquely striated (Figs. 4 and 4 a) and serrated on the edge. Moreover, 

 in old preparations the distal ends of these bristles break up into tufts of fine fibres. 

 The first tuft is smaller and the translucent tips less definitely formed than those which 

 follow, but the structure is essentially the same. The second series of bristles in each 

 tuft is considerably longer than in the previous forms (e. g. P. nesidensis), the tips almost 

 reaching the commencement of the wings of the distal series. Dr. Williams states that 

 the number of bristle-bundles on each side is sixteen, but he had probably omitted the 

 first. In transverse section the central region of the bristle presents the aspect of 

 severed fibres. Marenzeller and De St. Joseph mention a small papilla below each 

 setigerous process in segments 6, 7, 8 and 9. Such is observed in some examples from 

 the second bristle- tuft backward to the third or fourth. 



From each setigerous process an elongated and somewhat elliptical eminence having a 

 double row of golden hooks along the centre passes ventrally. Each hook (Plate CXXVa, 

 fig. 4 c) has a stout base which narrows upward to the curved neck, above which are 

 the chief fang and two teeth on the crown, in a diminishing series in lateral view. Curved 

 striae extend downward from the small teeth on the crown. The basal part of the hook 

 is marked by radiating striae. In the anterior hooks the third tooth on the crown is less 

 distinct than in the posterior. In front view two teeth occur in the middle. The double 

 rows are so arranged that the hooks lie back to back with the fangs pointing outward. 

 The one set may by fixing arrest the egress of the animal, and the other may in the same 

 way stop ingress. In some of these rows sixty- six hooks occur on one side and sixty- 

 seven on the other, and in a second sixty-two and sixty-four respectively, so that the 

 combined effect must be considerable. The rows are somewhat longer in front, and the 

 first (opposite the second bristle-tuft) has only a single series of hooks. The anterior 

 rows also have the glandular wedge which dorsally envelopes the bristle-tuft, and has its 

 apex about the middle of each interspace. By-and-by, however, this glandular tissue 

 diminishes to a narrow longitudinal belt between the last six bristle-tufts, the shortened 

 eminence for the hooks touching the base of the bristles. With the cessation of the 

 bristles the rows of hooks are confined to the lateral uncinigerous lamellae, which 

 continue to the posterior end, gradually diminishing in size as the slender tail is reached. 

 The lateral glandular belt is also continued from the bristled region backward between 

 the hook-lamellae, but stops short of the tail. On these uncinigerous processes the hooks 

 form a single row along the anterior edge, and at one end of the row a series of imperfect 

 hooks make a curve, those least developed having only a striated main fang, whilst those 

 touching the complete series show a crown above the fang, the base of the hook being 

 absent. The minute processes on the tail have few hooks. 



The hooks of specimens from the Channel Islands show the two teeth above the great 

 fang very distinctly, and so with those from Shetland. The anterior hooks of those from 

 Lochmaddy have considerably shorter necks than those from St. Andrews. The striae on 

 the neck of the hook are well shown in those from Cornwall. De St. Joseph observes 

 that the first six thoracic rows have a single row of ninety to one hundred hooks. 



