300 J. H. ASHVVOETH. 



21. Summary op Results. 



1. Specimens of Scalibregma iuflatum from the nor- 

 tlieru seas of Europe and America are not distinguishable by 

 any essential and constant character from those obtained by 

 the '' Challenger '^ in southern seas. 



2. The parapodia of the segments posterior to the fifteenth 

 or sixteenth bear dorsal and ventral cirri which contain large 

 unicellular glands, the secretion of which is in the form of 

 elongate fusiform rods. The fine- pointed tips of the glands 

 pass between the epidermal cells and open on the free 

 surface. The notopodium; its cirrus, and some of its setae 

 are formed in advance of the neuropodium and its corre- 

 sponding parts. 



3. The set^ of each ramus of the parapodium are of two 

 kinds : (1) simple capillary bristles, the distal third of which 

 bears (in unworn examples) a large number of minute hair- 

 like processes; (2) rather stouter, shorter seta9, furcate 

 distally, the two unequal pointed limbs bearing on their inner 

 faces a number of curved barbules. Both these kinds of 

 setae are found in the earliest recognisable parapodia. Fur- 

 cate setee of this type are practically restricted to the family 

 Scalibregmid£e. 



4. The dorsal vessel is dilated at two points to form the 

 blood-reservoir and the heart. There is no cardiac body in 

 the heart. 



5. The brain consists of an anterior lobe in relation to the 

 prostomial epithelium, and two posterior lobes, each applied 

 to the inner side of the corresponding nuchal organ. The 

 ganglion cells are found chiefly on the dorsal and ventro- 

 lateral faces of the brain. The anterior lobe gives off a pair 

 of nerves to the tentacles ; the cesoph-ageal connectives arise 

 from the middle region of the brain; the posterior lobes give 

 off nerves which run along the sensory epithelium of the 

 nuchal organs. In old specimens the fibrous part of the 

 brain becomes proportionately larger and more complex, and 

 the ganglion cells become aggregated into groups. 



