HYALINCECIA TUBICOLA. 423 



border of the tip is lanceolate, whilst the terminal process of the setigerous region is 

 small. At the twentieth foot the dorsal cirrus is more elongate; the posterior papilla is 

 shorter and more ovate, but the bristles have the same character. The setigerous region 

 is about the same length as at the tenth. 



The branchiae commence from the twenty-third to the twenty-sixth foot as a simple 

 filament, and continue almost to the posterior end. 



At the thirtieth foot the dorsal cirrus has diminished to a slender subulate organ, 

 whilst from the inner edge of its base arises a branchia more than twice its length and 

 bulk, and slightly fusiform in outline. The setigerous region is considerably shorter, 

 forming a short blunt cone with a trace of a papilla at the tip (and it disappears in the 

 next foot). Dorsally (above the spines) is a group of three longer winged bristles with 

 rather short tips. Brush-shaped bristles occur along with these. Then follow, below, 

 two strong bifid hooks with wings (Plate LXXXIV, fig. 8 c). Ventrally are about three 

 bristles with shorter tips and broader wings than those of the dorsum. The ventral pad 

 is the only representative of the ventral cirrus. The branchiae diminish in size posteriorly, 

 as also does the dorsal cirrus, but the arrangement of the bristles and hooks remains the 

 same. 



Posteriorly the body diminishes to a somewhat flattened tail, the last segment of 

 which is ovoid, with the anus on the dorsum and two long caudal cirri from the hind edge. 



In. an example procured in Norway by Canon Norman a subulate tentacular cirrus 

 of some length sprang from the middle of the first segment nearly in a line with the long 

 lateral tentacle of the right side. Such would seem to indicate that the absence or presence 

 of these organs is not a matter of fundamental importance, though it may be a convenience 

 in classification. In one of the British specimens a tail is being regenerated, and this 

 is tipped with three long and slender styles, one of which bifurcates near the tip. 



Fage 1 observes that the ectodermic portion of the segmental organ of this form is 

 particularly well developed. 



The tube (Plate LXIV, fig. 5 b) is a translucent horny structure, which the animal 

 drags after it like the larval Phryganea (Pruvot) 2 or other aquatic form. Schmiedeberg 3 

 has found a peculiar substance in it, which he calls onuphin, as well as an albuminoid 

 material. 



Reproduction. — De St. Joseph gives the diameter of the eggs in ripe examples from 

 St. Raphael at 0'24 mm., with a porous zona r-acliata. 



The original description by 0. F. Miiller (1788) is as definite as his figures, and he 

 specially points out the singular nature of its pellucid tube. 



The tube of this form is represented in Plate LI, fig. 4, of Montagu's MS. drawings 

 by Miss Dorville (1808) in the Linnean Society's collection. 



Grrube gave a brief description of the species from Mediterranean examples in one of 

 his early papers. 4 He thought the dorsal longitudinal muscles smaller than in Eunice. 



1 < Ann. Sc. nat./ 9 e ser v t. in, p. 350, fig. 37 (genital funnel). 



2 c Arch. Zool. exper./ 2 e ser., hi, p. 256. 



3 'Mitth. Zool. Stat. Neap./ in, p. 373, 1882. 



4 l Anat. u Physiol./ Kiemenw., p. 45, 1838. 



