16 Prof. Mcintosh's Notes from the 



on laceratioii of the wall. They are slightly yellowish, and 

 to some extent refract the light. In its native habitat the 

 tentacles are partially protected in extrusion by entering 

 the hollow processes of the fringe of the tube. 



The three branchiae form conspicuous and finely-branched 

 tufts on each side^ the first pair being the largest. All are 

 sub-dichotoinously branched, and the terminal divisions are 

 fine, so as to give the arbuscles a characteristic appearance. 

 Moreover, i\\Q\ also have a whorled aspect towards the tip. 

 The ultimate divisions are translucent, and have obscure 

 longitudinal striae, with cells and granules in the wall. The 

 first pair is situated on the narrow segment immediately 

 behind the collar, and a trace of which is seen in front of 

 the glandular ventral shield. 



The long body is moderately dilated anteriorly, and gently 

 tapered to the tail^ at the tip of which is the terminal anus 

 surrounded by a series of marginal papillae. The segments 

 are numerous, viz., from two hundred to two hundred and 

 eighty. The dorsum is rounded, the ventral surface grooved 

 throughout — often with a central ridge, — except the anterior 

 shields, which extend from the lower lip almost to the ter- 

 mination of the bristles. This glandular surface is divided 

 into segments — generally two in each body-segment — by 

 transverse furrows. Posteriorly it becomes narrow and ends 

 iu the median groove about the last bristle-bundle. Besides, 

 a glandular belt occurs at each side in the line of the bristle- 

 bundles, after the manner of the corresponding belt in the 

 jMaldanidsR, and it is continued backward considerably 

 behind the bristles. 



Tlie first segment is very narrow, and is enveloped laterally 

 by the free collar of the next segment. It bears the first 

 pair of branchiae, and forms a narrow rim in front of tlie 

 glandular ventral shields. The next has a greatly developed 

 anterior lamella or collar, which stretches from the edge of 

 the ventral shield almost to the second branchia — thus 

 forming the second process of this kind on each side. The 

 follownig segment has the third branchia and the first 

 bristle-tuft, but bears no hooks; The bristles are bound 

 firmly together in flattened fascicles and slope outward or 

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

 The bristles have a pale base, a shaft with fine striae iu- 

 ternally, and a tapering tip with a double wing, the latter 

 being obliquely striated. The first tuft is smaller and the 

 translucent tips less definitely formed than those which 

 follow, but the structure is essentially the same. Tlie second 

 series of bristles in each tuft is considerablv longer than in 



