28 EEPOET OF COMMISSIONER OF FISH AND FISHERIES. [322] 



The crooked, round, calcareous tubes'made by Serpula dianthua V. ? 

 are often to be found adhering to the under surfaces and sides of stones 

 Dear low-water mark, and also in the pools in more exposed situations ; 

 sometimes they are even aggregated together into masses. When dis- 

 turbed the worm suddenly withdraws its beautiful wreath of gills into 

 its tube and closes the aperture closely by means of a curious plug or 

 operculurn. This is placed at the end of a rather long pedicle, and is 

 funnel-shaped, the outside longitudinally striated and the edge bordered 

 by about thirty sharp denticles ; from the middle of the upper side 

 another smaller, short, funnel-shaped process arises, the edge of which 

 is divided into twelve or thirteen, long, rather slender, rigid processes, 

 which are usually a little curved inward at the top, but may be spread 

 apart in a stellate form. A small, rudimentary, club-shaped operculurn 

 exists on the other side. When these tubes are placed in sea- water and 

 left undisturbed for a short time, the occupant will cautiously push out 

 its operculuin and display its elegant wreath of branchia3, which varies 

 much in color in different specimens, but often recalls the varied hues 

 and forms of different kinds of pinks, (Diantkus.) The name which I have 

 given to it alludes to this resemblance. Fine specimens of this Serpula 

 may often be found, also, in the pools near low-water mark, attached to 

 the upper surfaces or sides of rocks, and in such situation they display 

 their charms to great advantage. The wreath of branchire is nearly 

 circular, consisting of two symmetrical parts, each of which is made up 

 of about eighteen pectinate branchi ; these are covered on their inner 

 surfaces with slender filaments which extend nearly to the ends, but 

 leave the tips naked. Young specimens have fewer branch ijic. In the 

 more common varieties these branchia3 are purple at base, with narrow 

 bands of light red or pale yellowish green ; above this they are trans- 

 versely banded or annulated with purplish brown, alternating with yel- 

 lowish green, or with purple and white ; the pinna3 usually correspond 

 in color to the part from which they arise, but are sometimes all purple. 

 In other specimens the branchiae are yellowish white, or greenish white, 

 banded with brown. In one variety (citrina) they are bright lemon- 

 yellow, or orange-colored, throughout. The operculum, in all the varie- 

 ties, is usually brownish green above, with the sides purplish brown, 

 lined with whitish near the edge, and with a greenish white band at the 

 base; the pedicle is usually purplish, with two or more bands of white. 

 The body is usually deep greenish yellow, with the back lemon -yellow ; 

 the collar is broad with an undulated border, and is pale green, veined 

 with darker green blood-vessels. This species is also often met with in 

 dredging on shelly bottoms. 



The Potamilla oculifera (Plate XVII, fig. 86) is another beautiful 

 annelid, related somewhat to the Serpula, but its tubes are tough and 

 flexible ; they are constructed out of fine sand and other foreign matters, 

 glued firmly together with the special secretions of the animal. These 

 tubes are often found attached to the under sides of stones, but, passing 



