12 Trot. Mcintosh's Notes from the 



The branchire are tlirce in number, the anterior l)eing tlie 

 lar{2;cst, the second and tliird re^uhirly diniinisliing. In 

 proportion to the size of the body they are somewhat larger 

 than in T. ncbuhsa and they have a stiffer outline. They 

 are diehotomously branched, and have very short terminal 

 divisions — a distinctive feature when contrasted with 

 T. nebulosa. 



The setigerous processes are seventeen in number^ the 

 first occurring close to the base of the last branchiae. The 

 bristles are long, translucent, slightly yellowish, and finely 

 tapered, and, as usual, in two series, a shorter and longer. 

 In the latter the wings are narrow' and indistinct, in the 

 former they are broader and easily recognized, but they do 

 not proceed to the finely tapered extremity of the bristle. 

 A curvature of the tip occurs at the winged region. Little 

 difference exists between the first bristles and the last^ except 

 in the fewer number as contrasted with the middle groups. 



The rows of hooks commence on the second bristled 

 segment, and they are comparatively short to the seventh 

 bristle-bundle, the last ten of the region being longer. 

 Moreover, whilst they form a single row in front, they are 

 arranged in a double row posteriorly (eleven to twenty 

 segments, Marenzeller), the great fang in each pointing to a 

 median line between the rows. Behind the bristles the 

 hooks are borne on an unciuigerous process or lamella, and 

 form shorter rows than in front. These lamellae have a 

 concave tiistal margin anteriorly, but posteriorly the tip is 

 birid, and the processes diminish much toward the tip of 

 the tail. 



The liooks somewhat resemble those of Polymnia nebulosa 

 in general form, but are readily distinguished by the presence 

 of a second tooth above the great fang and the somewhat 

 shorter base. 



In Polymnia nebulosa, jSIontagu, the seventh species, which 

 is found on both sides of Scotland, England, and Ireland, 

 the cephalic region is distinguished by the great size of the 

 upper collar or arch, and by its frilled inw^ard curve at each 

 lower edge. Its upper surface is somewhat flattened, that 

 is to say, only a shallow groove is present, the mass of 

 tentacles springing from tlie posterior half near the rim. 

 These tentacles are pale orange in life and spotted with 

 white, so as to give them a barred appearance, and their 

 movements are remarkable, for not only do they aid in the 

 construction of the tube, but hoist the animals up the per- 

 pendicular side of a glass vessel or in any direction^ and are 



