TEREBELLA. 235 



directed forwards ; the second is always naked ; but the third has 

 occasionally appendages similar to the tirst, except in being separate 

 at the base. Feet of the fourth and following segments of three 

 kinds ; first feet with a dorsal branch only with lance-shaped bristles ; 

 second pair and the succeeding, for a specific number, with a dorsal 

 setigerous branch, and with a ventral branch consisting of a double 

 series of hooks or uncini ; the segments posterior to these with the 

 ventral uncinated series only : branchiae in one, two, or three pairs, 

 inserted on the second, third, and fourth segments, near the base of 

 the appendages when these exist, arbuscular. Tube membranous, 

 coated with broken shell, gravel or sand, cylindrical, open at both 

 ends, erect or free. 



* Branchiae in three pairs. 



1 . T. conchilega, branchise arborescent ; setigerous feet 1 7 pairs, 

 on a lateral thickened band ; abdominal portion subannulose, with 

 numerous uncinated papillary feet on equal and similar segments. 

 Tube cylindrical, coated with fragments of shells, as thick as a quill. 

 Length 6". 



Nereis conchilega, Pall Misc. Zool. 131. tab. 8. f. 14-22. 



Terebella conchilega, Savign. Sj/st. Annel. 85. Grube, Fam. Annel. 80. 



Hab. The coralline or laminarian region. 



Obs. Pallas says that the abdominal portion consists of as many 

 as 150 segments, while Savigny tells us that the entire body has 

 only 134, of which 114 belong to the abdomen. This difference 

 does not indicate any difference in species, for, as a character, num- 

 ber of segments (as of tentacula and branchial filaments) is of no 

 value, their evolution being successive, and consequently varying 

 with the age and size of the individual. According to Savigny, the 

 worm attains the length of 8 or 9 inches. 



(a) No locality. 



2. T. littoralis, branchise arborescent; setigerous feet 16 pairs, 

 on a thickened base along each side ; skin smooth, unspotted. 

 Length 4-5". Tube coated with sand or gravel, with a tuft of 

 branched filaments around its upper orifice ; buried erect. Length 

 6-12". 



Sabella chrysodon, Mont. Test. Brit. 546. 



Terebella conchilega ?, Quatrefages in Cuv. Regn. Anim. illustr. Annel. 



pi. 3.f. 1. 

 Terebella littoralis seu arenaria — the Sand Mason, Dalyell, Pow. Great. 



ii. 183. pi. 26. f. 1-7. 



Hab. Between tide-marks in bays, burying its tube in sand and mud 

 mixed with gravel, the crested orifice raised about an inch above 

 the surface. 



