330 PRAXILLELLA (?). 



hooks differ from the typical forms in their shorter and less-boldly-curved shafts, shorter 

 necks, which are less dilated distally, in the larger angle made by the main fang and the 

 neck, and in their much natter crowns, three or four teeth only being visible behind the 

 great fang ; and the gular bristles are rudimentary, passing obliquely upward close to 

 the main fang. The first hook of the row in the third foot is even more rudimentary, as 

 shown by the blunt tip of the large fang, the fusion and indistinctness of the teeth on the 

 crown, and its short and nearly straight shaft. Such may, however, be an undeveloped 

 or developing form. The hooks of the last row (nineteenth row, Plate CIX, fig. 13 c) 

 retain much of the typical structure, though their shafts are shorter. Five or six teeth 

 are visible on the crown above the main fang, and the shoulder is largely developed. The 

 bristles of this region consist of the two groups, the stronger having narrow wings, and 

 the slender forms are few in number and extremely attenuate. 



A large, though softened and fragmentary example, dredged by Dr. Grwyn Jeffreys 

 off the Hebrides in 1866, has hooks which differ from the foregoing, not only by their 

 great size, but in the presence of a distinct ridge or process for the gular bristles. There 

 are twenty-seven short cirri on the funnel, but no longer process, though one is double. 

 The same condition is seen in certain forms dredged at Nos. 35 and 36 and in 125 fathoms 

 off Cape Rosier, Canada, in 1873. Further investigation of these is necessary, as they 

 may pertain to other species. 



A large example from the Outer Haaf, Skerries, Shetland, had the rim of the cephalic 

 plate less developed and the an tero -lateral margins slightly crenate, but otherwise it does 

 not seem to differ. A specimen of medium size, again, from a depth of 90 fathoms off 

 North Unst, presented a very long process for the dorsal bristles in several of the posterior 

 segments (even to the third from the anal funnel), so that the feet at first sight appeared 

 to have a short cirrus. 



The tubes are composed of sand, with a lining of tough secretion. They are 

 comparatively soft, though in small specimens from the Outer Haaf, Skerries, the minute 

 grains of sand and shells cling tenaciously to the lining. Fragments of shells and of tubes 

 of Ditrypa are attached to some tubes procured in the same region. 



Regeneration of lost parts readily occurs. Thus, where severance of the body at the 

 seventh bristled segment had taken place in an example from the Outer Haaf, Skerries, 

 the anterior end forms a smoothly-rounded surface between the ridges for the hooks, whilst 

 the ventral median line is elevated into a keel which extended along the posterior half of 

 the segment. 



Fauvel (1909) regards P. arctica as a synonym of this species. 



In certain varieties of Praxillella praetermissa the anal ring bears longer and narrower 

 cirri, such as Arwidsson shows in P. affinis, yet the hooks and other parts remain typical. 



4. Praxillella (?). No gular bristles. 



Dredged in the 'Porcupine' Expedition of 1870; locality not stated. Two 

 segments from the middle of a fairly large species, in which both the bristles 

 and the hook-rows are conspicuous. The bristles are long, strong, and golden, striated 

 longitudinally, and with a distinct but narrow wing at the slightly curved and finely 



