174 THELEPUS CINCINNATI^. 



as such as far back as the thirtieth bristle-bundle. Moreover, a thick glandular coat 

 invests the body laterally, -enveloping the tori and the setigerous processes in each 

 segment. In large examples the anterior scutes are rugose transversely, and cut into 

 various folds in each segment. In Thelepus cincinnatus, Fabr., between the setigerous 

 process and the hooks from the fourth to the seventh segment a papilla occurs at the 

 dorsal end of the hook-row, the first being smaller than the rest. These are not readily 

 seen in the British form, in which the glandular cushions running outward from the 

 ventral scutes anteriorly are much more prominent. In several from Balta (50 fathoms), 

 however, these small papillae were present. 



In many the posterior region is absent, and it is evident that the fragility of this 

 part is great, for reproduced tails are common. In a specimen about If inches in 

 length the regenerated tail (Plate CXX, fig. 1) had a regular series of rounded papillae 

 externally and a smaller series internally, the anus being in the centre. Slight grooves 

 pass forward for a short distance from the intervals between the papillae. 



The body is of a reddish, orange or pale orange inclining to yellow with the tints 

 deeper anteriorly, and dorsally either pale or dark toward the posterior end. The 

 ventral "scutes" are white. Most of the specimens from Lochmaddy are without dots; 

 indeed, only a single example showed a series of reddish-brown specks scattered over 

 the dorsum, none occurring on the under surface. The first segments are paler than 

 the succeeding— both dorsally and ventrally, and slightly striated longitudinally. The 

 tentacles are pale rose; the branchiae pale yellowish. 

 The ccelomic fluid is abundant in this species. 



The intestinal tract consists of a muscular oesophagus with strong circular and 

 longitudinal non-striated fibres, followed by the more flexible portion with a yellow 

 glandular coat, then the gizzard, and finally comes the wrinkled intestine with its 

 " chlorogogenous " sheath. The oesophagus is generally empty ; the flaccid region 

 behind, when the animal has recently fed, has usually three or four large swellings so 

 as to be moniliform. The contents of these are muddy sand containing organic particles 

 such as diatoms. In one example the last swelling was partly bounded by the anterior 

 part of the gizzard, which, however, throughout the rest of its extent was of the normal 

 size. Dr. Williams states of this " gizzard-like part": "It is generally found on 

 examination to be devoid of contents; the alimentary substance does not stop or lodge 

 in it." In this case the gizzard contained a small quantity of the same muddy sand as 

 the tract in front. In the normal condition it is unlikely that over-distension of the 

 main part of the gizzard ensues, since its function is probably to triturate the muddy 

 sand and render the organic particles available for absorption, and such would also be 

 facilitated by the limited quantity in it. 



Segmental Organs. — These are characterised by their greater length than those of 

 Lanice conchilega, and in the normal condition lie flatly along the ventral wall with 

 the free ends directed backward. They contain cellulo-granular structures and oil- 

 globules, and often assume a peculiar moniliform aspect in spirit. In some rounded 

 bodies like cells occur in masses. 



The feet are represented by setigerous processes and tori uncinigeri. The first 

 setigerous process arises dorso-laterally below the second series of branchiae, and the 



