36 AMPHTOTBNID^J. 



and Amphictene rested only on secondary characters. Pectinaria was characterised by 

 Malmgren as having an entire fleshy cephalic region and the tube straight. 



Meyer 1 (1887) remarks that at Naples the Amphicteniens are normally herma- 

 phrodite. 



The Amphictenida? formed, along with the Ampharetidas and Terebellidge, Levinsen's 

 group Terebelliformia (1883). after the arrangement adopted by Malmgren and others, and 

 there is some justification for this view. He included all the Amphictenidas under the 

 genus Pectinaria. 



The circulatory and digestive systems of Pectinaria belgica, Amphictene auricoma and 

 Petta pusilla were carefully described and figured by Wiren 3 (1885). 



Fauvel 3 (1903) describes the form and structure of the tubes of the AmphictenidaB, 

 the glands supplying the cement and the habits of the annelids. He subsequently (1907) 

 gave an account of the circulation in Lagis Koreni. The account of the intestinal sinus, 

 the large size of the ventro-pedal vessel of the first and second segments, and the occur- 

 rence of contractile ampullse on them, the structure of the heart, and the indirect 

 communication of the intestinal circulation with the ventral trunk are amongst the 

 salient features of this paper. 



The Amphictenidse were placed after Terebellides at the end of the family 

 Terebellidse by Dr. Johnston (1865). 



Three pairs of organs of Bojanus are described by Cosmovici (1880) in the anterior 

 region of the body of the Amphictenida3. The first pair have the form of closed glandular 

 pouches. The other two are attached to the segmental organs, which are flask-shaped, 

 with a posteriorly directed funnel-shaped internal opening and an external pore. The 

 backwardly directed internal aperture is considered by the author to be related to the 

 position of the genital products which lie on each side of the nerve-cord posteriorly. 



D. Mlsson 4 (1912) gives a detailed account of the nervous system and sense-organs 

 chiefly of this family, and he contrasts the arrangement of the cephalic ganglia of the 

 AmphictenidaB and Ampharetidse with those of the errant forms— all being essentially 

 three-lobed, as Pruvot and Racovitza showed. Whereas, however, the ganglia in the 

 free-living forms are arranged (diagrammatically) like an H or a K, those of the two 

 families mentioned are in the form of a crescent. He describes in the branches of the 

 nerve-cord of Pectinaria belgica a motor dorsal and a mixed ventral root, and he gives a 

 figure showing both segmental and intersegmental nerves to illustrate this condition. 

 The former (dorsal) root supplies the longitudinal muscles, the latter (ventral) the circular 

 muscles and sensory structures. Further observations on this subject would be interesting. 

 Nilsson's account of the nervous system and sense-organs specially deals with Lagis 

 Koreni, Pectinaria belgica, Amphictene auricoma and Petta pusilla, and he points out that 

 the scapha (with its eyes in Petta) has its nerve-supply from the posterior gastric just as 

 the buccal region has its nerves from the stomato-gastric. The fine nerves on the veil, 

 and the nerve-cells of the nuchal and side organs are figured and described. Finally he 



1 ' Mittheil. Zool. Stat. Neap./ viii. 



2 < Kongl. Sv. Yet. Akad. Handl./ Bd., xxi, p. 22, etc., Taf. iii, figs. 1—5, Taf . iv, figs. 9, 10, 

 Taf. v, Taf. vi, figs. 8, 9. 



3 ' Mem. Pontif. Accad. Romana N. Lincei/ vol. xxi, pp. 1—28, with text-figs. 



4 'Zoologiske Bidrag Uppsala/ p. 85, Taf. iii— v, 1911— -12. 



