Gatty Marine Laboratory, St. Andrews. 173 



The firm cylindrical region, which splits in front to form 

 the two pillars of the crown, has at its posterior border 

 several processes, which apparently pertain to the next 

 segment. 



Dorsally is a pair of branchiae of the normal shape, and 

 from this a fold passes ventrally on each side, a space, 

 however, intervening between it and the outer limb of the 

 bifid postoral process. At the end of this ridge is a broad, 

 flattened, pointed lobe or papilla, and sometimes two occur. 

 Such would appear to indicate the first foot of the anterior 

 or thoracic region of the body, more especially as on each side 

 of the mid- dorsal groove a tuft of three long simple bristles 

 with striated shafts and translucent tapered tips imbedded 

 in the tissues passes forward to the anterior crown. The 

 inner bristle on each side forms a pair with its neighbour 

 and the tips are slightly incurved toward each other, the 

 second and third (outer) are smaller. These bristles pass 

 forward in a nearly parallel manner, only very slightly 

 widening in front. The most interesting feature, however, 

 is the occurrence to the exterior of these, also imbedded in 

 the tissues, of several types of the modified bristles in the 

 paleal crown. Thus the slipper-shaped kind with the shaft 

 coming off at an angle, the form resembling a broad and 

 short bill-hook, and the broad paddle-like external paleae 

 with the lateral spikes and special central process are each 

 represented on one side or the other. 



The anterior ("thoracic") region of the body includes 

 three segments with transversely elongated lamellae, each, 

 moreover, having a pair of flattened ligulate crenate branchiae 

 which taper to a point and somewhat resemble the horns of a 

 goat or antelope, from their transverse ridges, the large cilia 

 of which have a bold hook-like curve directed toward the tip 

 of the organ. The branchiae are supplied with long powerful 

 cilia on their ridges, which make a vortex in the water 

 around them, and thus are in marked contrast to the 

 delicately ciliated tentacles. Two vessels occur at their 

 base, apparently afferent and efferent, and between these are 

 a series of parallel transverse branches. They are less 

 sensitive than the pale purple tentacles, since a more violent 

 contraction takes place when the latter are touched with a 

 needle. The first, viz., that in front of the anterior region 

 proper, is a rather broad tongue-shaped process, shorter than 

 the succeeding, which are elongated horn-shaped organs, the 

 6th apparently being the longest. They continue to the 

 posterior end, but gradually diminish in size. 



Each of the three prominent lateral lamellte below the 



