AMPHICTENID^E. 33 



Horst 1 (1881) investigated the development of Sabellaria (his Eermella) alveolata at 

 Wimereux and corroborated some of the points, such as the formation of a perivitelline 

 space, mentioned by De Quatrefages. He believed that more spermatozoids than one 

 entered the ovum, that, in contradistinction to De Quatrefages, the first plane of segmenta- 

 tion occurs in the direction of the point where the polar globules appeared. He differs also 

 in regard to the segmentation, and found that the " animal spheres " surround the 

 vegetative part of the ovum, forming an " amphiblastula." When four days old the larva 

 has a dome-like form with a cephalic tuft of long cilia and the peritroch, and there are a 

 mouth and ciliated oesophagus separated by a constriction from the gut. There are four 

 provisional setaB and two ocular patches. His figures are good, the latest (metachete) 

 stage of the larva with its long spinous temporary bristles and reddish pigment being 

 characteristic. 



Griard 2 (1913) noted that Axionice flexuosa frequently occurred at Wimereux in 

 masses of Sabellaria alveolata. He may refer to another form. 



In the British Museum an example from Sanclgate, Kent, has Sabellaria crassissima 

 over the old label Alveolaria arenosa, Mus. Leach. It is further interesting that the 

 Sabellaria saxicava, Baird, is only an ordinary example of the genus in the usual tube of 

 coarse sand which has subsequently been coated with Lithothamnion. It came from 

 Vancouver Island. So far as known there is no borer in the family. 



Hornell (1891) mentions that a mite is frequently found parasitic on this species in 

 the Liverpool district (Hilbre Island). 



Family XXVII. — AMPHiOTENiDiE, Malmgren, 1866. 



Amphitrite, 0. F. Miiller ; Terebellum, Denys de Montfort ; Pectinaria, Lamarck ; 

 Amphictenea, Savigny, Grube. 



Cephalic region obliquely truncate or semicircular, with two rows of powerful golden 

 bristles (paleolae) nine to seventeen in number which exactly fit the aperture of the tube, 

 and which are compressed, tapered and arranged in contiguous series in two rows 

 attached to the buccal (second) segment. Above the paleolas is a firm region with a 

 smooth or fimbriated border, whilst beneath them is the membranous fan-shaped veil 

 with cirri on the margin (rarely entire). To the base of this on the dorsal arch of the 

 mouth a group of contractile grooved tentacles is affixed on each side. Tentacular cirri 

 two, the anterior springing from the side of the head, the second from the first segment. 

 Body of comparatively few segments, and of several regions differently constituted, viz., a 

 buccal, an anterior or thoracic region, large and devoid of hooks, a posterior (abdominal) 

 region with prominent lamellse for hooks, and lastly a short posterior appendicular 

 or caudal region of about five to six segments (scapha), usually bent at an angle, 

 excavated above and convex ventrally, the margin crenulate and with a valvular 

 flap above the anus. Intestine longer than the body. Ccelom with one anterior 



1 ' Versl. en Meded. afd. Nat ark. Amsterd./ 2 d R D e xvi, pp. 207—214, and plate. 



2 CEuvres Div., p. 57. 



174 



