LAGIS KORENL 53 



third hook-lamella posteriorly and the blood comes from below. The former contracts 

 from behind forward, squeezing the vessel into a pale thread. The skin is minutely 

 reticulated with red capillaries, and two large lateral trunks are seen on the ventral 

 surface. The first two ventral ridges have a series of brownish-red grains scattered on 

 their posterior surfaces. On the ventral surface is a lateral trunk on each side which 

 carries the blood backward. The caudal process has pale papilla along its sides. 



In life the bright red branchiae are most sensitive organs, now being gently extended 

 so as to expose each lamella separately to the water, and again abruptly contracted into a 

 mass. They are usually two in number, though occasionally the posterior on one side is 

 absent. The anterior lies immediately behind the long lateral cirrus and has the form of 

 a coiled process placed transversely, to which are attached many membranous leaf -like 

 plates which gradually diminish in size toward the tip, the whole somewhat resembling 

 the antenna of a lamellicorn beetle or the scorpioid cyme of Forget-me-not, or Borage. 

 With the leaflets crowded so thicklv, the coiling of the axis and the diminution of the 

 lamellae at the tip present special advantages for aeration. The second branchia arises 

 from the dorsal edge of the segment-ridge behind the former, and its structure is the 

 same. The organs are firmly attached to the skin, and in softened examples are removed 

 with it. 



Cement-glands with muscles occur in the body (not the coelom) at the sides of four 

 segments, with a duct which opens near the first branchia (Hessle). 1 



Dorsally segmentation is less evident, but on the ventral surface the median and 

 lateral ridges give more definition in this respect. A flat papilla, from which a ridge 

 and groove run to the mouth, lies within the long cirrus behind the veil. Then a median 

 fold behind the mouth is continued laterally to the first branchia. This is followed by 

 another median elevation or a boss with a ridge on each side to the second branchia. 

 The parts, however, vary much according to the degree of contraction or extension, the 

 first-mentioned median fold in extension becoming a boss, in front of which a groove with 

 a fillet at each side passes to the mouth. Behind the second branchial ridge is a distinct 

 and longer one on each side of a median elevation, and terminating laterally in the first 

 bristle-papilla. The bristle-tufts are directed upward and backward, commencing with 

 three smaller tufts, the first two of which spring from the outer ends of ventral ridges 

 connected with median elevations, whilst the third has only a lateral lamella. No hooks 

 occur on these anterior feet. The fourth foot presents a large lamella and stronger 

 bristles, and the five or six following have also strong bristles, after which they diminish 

 to the last, which is minute — that is, not half the size of the first tuft. The structure of 

 all these tufts of somewhat brittle bristles is the same, though the anterior and especially 

 the posterior show certain modifications. Each has two kinds of stout bristles, viz., 

 (1) that in which after widening a little above the base the strong shaft tapers gradually 

 to a somewhat rigid, sharp tip (Plate CXXIV, fig. 3 c), and (2) a shorter series in which 

 the stout shaft tapers to the commencement of the translucent terminal portion in which 

 a rudimentary double wing appears, and then it dilates into a flattened spear-head tapered 

 to a fine point (Plate CXXIV, fig. 3 b). The broad, 'flattened tip is marked by fine striae 

 directed distally. The serrations are large at the base of the terminal region, rapidly 



1 ' Zool. Bidr. Uppsala/ p. 52, 



