382 Prof. M'Intosli's Notes from the 



De St. Joseph* found it common on shell and oyster- 

 grounds frequented by Sabellaria spinulosa off Dinard and 

 St. Malo, at a depth of 7-25 metres, and corrected Grube's 

 view of the ocular points. 



The family Telethusae or Arenicolidae is represented by 

 three species, viz. Arenicola marina^ L., A. ecaudata, John- 

 ston, and A. gruhei, Clapar^de, as recently and excellently 

 described by Drs. Gamble and Ashworth in several publica- 

 tions, the iirst-mentioned representing the tailed group, the 

 two latter those in which the branchicfi go to the posterior end. 

 Constantly sought on every suitable beach for bait, no marine 

 form could illustrate better than Arenicola marina the 

 permanence of such a marine type, notwithstanding man's 

 efforts to destroy it. Yet it is always easily reached by 

 man, whereas the food-fishes have the wide ocean and all its 

 manifold arrangements as safeguards. This species is 

 ubiquitous in its distribution on the British shores, whereas 

 A. ecaudata is a western and southern form, and so is 

 A. grubei. Several stages in the development of Arenicola 

 ecaudata may be referred to. The smallest example procured 

 jbetween tide-marks at Lochmaddy, North Uist, in August, 

 measures about 4 mm. in spirit, but it would probably stretch 

 considerably more in life. As Dr. Ashworth points out, there 

 is no abrupt narrowing of the caudal region as in the pelagic 

 young of ^. marina procured at St, Andrews in the bottom- 

 net. No branchise are present. The anterior rings are wide, 

 the posterior narrow. There are between fifty and sixty 

 bristled segments. The next stage is represented by a 

 specimen 7 mm. in length from the same locality and on the 

 same date. In front of the first bristle-tuft are the somewhat 

 large blunt prostomium and five rings. The setigerous lobes 

 are distinct, and the first gill arises on the sixteenth. As the 

 anterior segments are much broader than the posterior, the 

 branchial region occupies less than half the length and is 

 characterized by a deep furrow on the dorsum. In the anterior 

 half a single ring is interpolated between the setigerous lobes, 

 but the feet are so crowded posteriorly that no more than one 

 ring to each segment is present at this stage. The branchiae, 

 which number more than forty pairs, consist for the most part 

 of simple filaments or a pair of filaments, and they appear to 

 be largest anteriorly. The bristles are proportionally longer 

 than in the adult and have a trace of a wing on each side. 



* Ann. Sc. Nat. 8^ s^r. t, xvii. p. 104. 



