Gatly Marine Lahoratory^ St. Atidnws. 17 



tlie previous forms (e. g., T. nesidensis) , tlie tips almost 

 reaching the commencement of the wings of the distal series. 

 Dr. Williams states that the number of bristle-bundles ou 

 each side is sixteen, but he had probably omitted the first. 

 lu transverse section the central region of the Iristle 

 presents the aspect of severed fibres. 



From each setigerous process an elongated and somewhat 

 elliptical eminence, having a double row of golden hooks 

 along the centre, passes veutrally. Each has a stout base 

 which narrows upward to the curved neck, above which are 

 the great fang and two teeth on the crown — in a diminishing 

 series in lateral view. Curved strise extend downward from 

 the small teeth on the crown. The basal part of the hook is 

 marked by radiating strise. In the anterior hooks the third 

 tooth ou the crown is less distinct than in the posterior. 

 In front view two teeth occur in tiie middle of the crown. 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 tlie 

 combined effect must be considerable. The rows are some- 

 what 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 envelops 

 the bristle-tuft, and has its apex about the middle of each 

 interspace. By-and-by, however, this glandular tissue 

 diminishes into a narrow longitudinal belt between the last 

 six bristle-tufts, the shortened eminence for the liooks 

 touching the base of the bristles. With the cessation of 

 the bristles, the rows of hooks are confined to the lateral 

 uncinigerous lamellse, 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-lamella3, 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 ninth representative, Loimia gigantea, Montagu 

 Ann, & Mag, N, Hist, Ser. (S. Vol. xv. 2 



