Gatty Marine Laboratory ^ St. Andrews, 25 



The posterior bristles are brittle, aud few remain after 

 capture. They have the same structure, but the knife-edge 

 process at the tip is shorter and the serrations of the edge 

 longer and coarser. 



From first to last the setigerous processes are closely 

 associated with the ridges for the hooks, and indeed form 

 part of them, finishing, as it were, the dorsal end by a 

 pointed process. Anteriorly the process is nearly transverse, 

 but by-and-by it slopes backward, especially posteriorly, 

 where the bristles pass from its posterior and upper angle. 



The hooks commence on the ridge, passing from the first 

 bristle-tuft ventrally toward the shields (fifth segment, 

 De St. Joseph), and the succeeding ridges gradually increase 

 in prominence until they are conspicuous latero-ventrally. 

 The first row is single, but at the eleventh a double row 

 occurs, and this continues a considerable distance, but on 

 the small posterior ridges only a single row is found. The 

 typical hook has a large main fang and three teeth above it, 

 tlie posterior margin is nearly straight, its distal end curving 

 to the crown, and its basal bending outward to form a 

 process of the base. The latter is of moderate length, 

 convex inferiorly, and with a sinuosity in front. The curve 

 beneath the great fang is abrupt and ends in a prominent 

 process, and below it a curve goes to the anterior prow. Al- 

 though only three teeth are observed above the great fang 

 in profile, numerous teeth appear when the crown is viewed 

 from above. In the first row of hooks the bases are altered, 

 the anterior prow being prolonged, and the sinus above the 

 bases posteriorly being more pronounced than in the typical 

 book. Anteriorly the outer edge of the groove for the 

 hooks is free, so that it sometimes resembles a papilla. 



From the Zetlandic seas comes Laphania boecki, Malm- 

 gren, the fifteenth form, in which the cephalic lobe is so 

 little developed that at first sight it has some resemblance to 

 a Maldanid. The dorsal collar, however, is present, and 

 the j)late passes obliquely forward to make a fairly firm arch 

 over the mouth. From the surface of the plate spring a 

 series of moderately elongated grooved tentacles. A small 

 tongue-like process lies in the pit below the mouth, whilst 

 the lower lip is thick and curved. 



The body is slightly dilated anteriorly, remains for some 

 distance of nearly the same diameter, and then gently tapers 

 to the tail. In the preparations the anterior end is generally 

 curved ventrally so as to resemble a Maldanid — as, indeed, 

 the firmness, the ventro-lateral ridges, and the posterior 

 segmentation also do. It is rounded dorsally, flattened 



