7« 



are somewhat stout, with tapering, winged tips ( a ) which often 

 show a spHt {b) in the wings from friction, thus giving the tips 

 a peculiar appearance, especially as a change seems to take place 

 thereafter. The last bristle-bundles are small, but show similar 

 structure, except that the shaft dilates towards the tip, which is 

 often split as in front. 



The hooks (Plate VH tig. 36) approach those of Pcctiiuir'ni, 

 in so far as below the eight upper and boldly curved teeth is a 

 short portion of the margin armed with minute teeth above the 

 truncated inferior angle. As the tip of the last large tooth 

 curves over these they are often indistinct. 



The alimentary canal wa.'^ distended with white sand — like 

 coral sand, much of which disappeared on the addition of acid. 



The beautiful, straight tube formed by the animal was almost 

 entirely composed of spicules of sponges in short lengths 

 placed transversely and fixed by secretions so as to form a per- 

 fectlv roimd tube 115 mm. in length gently tapered from the 

 wide to the narrow end, the former having a diameter of 15 

 mm., the latter of seven or eight mm. The spicules appeared 

 to be of the same size throughout the tube, which presented no 

 special lining, the inner surface being as smoothly and neatly 

 formed as the outer, though under the microscope the minute 

 reticulations or cells of the cement often stretched over the 

 component spicules. 



The labour involved in selecting ^.'^c\ fitting with such mar- 

 vellous skill the sponge-spicules comp-jsi-ig a tube so large 

 must have been both continuous and considerable. Moreover,, 

 the smaller end of the tube had a diameter of seven or eight mm., 

 so that in view of P. Fauvel's statement that but one tube suffices 

 for the life of the animal, we are left in doubt as to how it 

 fared in its earlv condition. In the preparation about an inch 

 of the tail projected beyond the small end of the tube. 



As stated, the intestine showed that the annelid frequented 

 calcareous sand, and, therefore, specially selected the sponge- 

 spicules for the formation of its tube. As this example was 

 procured between tide marks, the conditions are wholly 

 different from similar tubes formed by the deep-sea representa- 

 tives of the family. 



The account of the genus Pectinaria by Malmgren differs 

 from the condition in this example in so far as the marginal 

 lamina of the area on the ventral aspect of the paluhv is not entire, 

 but has at each side a series of acutelv conical smaller limbria', 

 followed by larger and somewhat triangular processes of con- 

 siderable breadth, which occupy the central region, lliere are 

 16 instead of 17 bundles of bristles, but only 13 rows of uncini^ 

 beginning at the fourth bristle-bundle. The minute structure 

 of the hooks corresponds with that of examples of Pectinaria 

 hclilica from various regions, and it may be that variation 



