9 
ANALYTICAL INDEX. 341 
CHAPTER IV.—continued. 
§ 1. Introductory remarks, ‘ : PAGE 130 
Two worms of the genus Nais inhabit the fresh-waters 
of Scotland, . : : : : ib. 
I. Nars.—§ 1. Nats uacustris, : . : 5 ib. 
Animal described, . : : : : 131 
M. Duges,—propagation, ib. 
Dwells among the roots of the Trig and becectan : ib. 
Plate XVI. explained, . : : : ib. 
§ 2. Nats PROBOSCIDEA, . p 5 : 5 ib. 
Animal described, é : p ; ib. 
Motion undulatory, A : : 5 132 
Plate X VII. explained, : c : ib. 
II. Lumpricus, : ; é : : : : ib. 
New class Annelides, F : : 5 ib. 
§ 1. Lumericus crrratus—The Medusa Worm.—CirraTuLus 
BOREALIS,—Lamarck, a A é 133 
Animal described, . - : F : ib. 
Its appearance seems to depend on age, 134 
Dwells in muddy fissures of rocks, . 5 : ib. 
Retreats from the light, ° : 4 ib. 
Ova, - : : c 5 : ib. 
Account of specimens, . - ; 3 ib. 
Plate XVIII. explained, . : : A 135 
§ 6.—Lumpricus MARINUS—ARENICOLA PISCATORUM—Lug 
Worm, ib. 
Pyramids of sand on the sea- ioe heoent up i this animal ib. 
Called the fisherman’s worm, : : é 136 
Description of the animal and its habits, : ib. 
Distinctive character of the species consists in the branchiew, 137 
2. Another species inhabits the Scottish seas, : ib. 
Form and organs of the animal described, 5 ib. 
Colour very dark green, : é 5 ib. 
Best specimens from Zetland, ; 5 5 138 
Extensively used as bait, : 5 - ib. 
Plate XIX. explained, : : : 3 ib. 
