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of Edinburgh, Session 1875 - 76 . 
coat, at the gap between the ventral longitudinal muscles. The 
area is small and flattened, and has a large neural canal in the 
centre superiorly. The oblique muscles are attached above the 
area. A similar arrangement occurs in Nicomache lumbricalis, 
Fabr., and in a large Canadian species of the same genus. 
AmmociiaridjE. —About a quarter of an inch behind the snout 
the nerve-area in Owenia filiformis , D. Ch., forms an ovoid mass 
outside the tough basement-tissue bounding the great longitudinal 
muscular layer. The area is entirely hypodermic, and as very little 
of this tissue remains in the majority of the preparations, the 
cords are often bare. The oblique muscles are not visible, and the 
longitudinal are only separated in the median line dorsally and 
ventrally. 
HERMELLimE. — In Sabellaria spinulosa , R. Leuckart, the cords 
remain quite separate throughout their entire length. Anteriorly 
each is placed in the substance of the great ventral muscle, near 
its upper and inner border. No distinct oblique muscles appear in 
this form. Posteriorly the nerves occupy the same relative position 
in the. diminished muscles, and each has a large neural canal at its 
inner border. 
Amphictenid^e. — In Cystenides hyperborea, Mgrn., the united 
cords in the anterior region occur as an ovoid mass over the trans- 
verse muscular fibres in the ventral median line. The large oblique 
muscles are widely separated from the nerve-trunks. 
Ampharetid^e. — In Amphideis Gunneri , from Canada, the nerves 
(in transverse section of the body-wall) appear as two minute sepa- 
rate bodies enveloped in a common neurilemma lying in the thick 
hypoderm of the median ventral region. Internally are the fibres 
of the circular coat and the insertions of the oblique and vertical 
muscles. 
Terebellid^e. — Anteriorly in Terebella nebulosa , Mont., the nerve- 
cords are placed outside the transverse band of fibres (part of the 
circular coat) between the oblique muscles, and therefore are hypo- 
dermic. The same arrangement occurs posteriorly. In Polycirrus 
aurantiacus, G-r., the cords have the same relative position, only 
they are considerably larger— a feature of interest in connection 
with the phosphorescent properties of the species. Within the 
circular coat is a small median longitudinal muscle. In Terebel- 
