8 OPHELIIDjE. 



Meyer 1 found three groups of ganglia in Polyophthalmus pictus — viz. anterior, middle, 

 and posterior. Pruvot, again, in the ordinary Opheliidao, described the posterior lobe as 

 double — in connection with the nuchal organs. Kiikenthal also states that there are three 

 pairs of ganglia, but Racovitza 2 adversely criticises the views held by this author. 



Ray Lankester 3 (1893) states that in Ophelia the vascular fluid contains a small 

 number of corpuscles, amoeboid in character, and which are impregnated with haemoglobin 

 from the surrounding fluid. 



Benham's fifth sub-order of the Nereidiformia is the Scoleciformia, and it includes the 

 Opheliidge, Maldanidao, Arenicolidse, Scalibregmidse, ChlorasmidaG (his Chlorhsemidse), and 

 Sternaspidse, a more or less doubtful association. The Polychaets do not lend themselves 

 readily to such associations. 



Schaeppi 4 (1897) carried out an investigation into the chloragogen of Ophelia 

 radiata, his conclusions being that the lymph-cells take their origin in the peritoneum, 

 and that the rod-cells and rods are genetically identical. The blood-system in the abdo- 

 minal region consists of a dorsal vessel, the homologue of the gut-sinus, and a ventral 

 trunk, and in the thoracic region of a dorsal vessel and a ventral, the homologue of the 

 gut-sinus. The heart-body is not a glandular but a valvular structure. The alimentary 

 epithelium contains chloragogen nuclei. The chloragogen of the peritoneum, the nephridia, 

 and the connective-tissue of the sinuses contain guanin ; that of the lymph-cells, the 

 blood-cells, and those of the alimentary- canal he calls Chitinchloragogen. This author 

 thought the rich folds of the stomach and gullet connected with alimentary respiration in 

 Ophelia. 



Philippson 5 (1899) reviews the relationships of this family with other families of 

 Polycha3ta, and thinks they most nearly approach the Ariciidas. He then considers the 

 affinities of the various genera of the Opheliidse amongst themselves. The most primitive 

 condition, according to him, is found in Armandia and Ammotrypane. Polyophthalmus, 

 again, is specialised for locomotion, whilst Ophelia and Travisia are adapted for a sedentary 

 life. Lastly, he follows Racovitza in his interpretation of the nervous system of the 

 group. 



Bullot 6 (1904) performed experiments on the grey eggs of Ophelia, using KCL in the 

 sea-water without fertilisation, and he found that the parthenogenetic larvse arose from 

 eggs which segmented regularly. In the case of fertilised eggs progress was more rapid, 

 the proportion of larvse was greater, and they survived longer. These experiments were 

 suggested by cases in which eggs producing larvse did not always segment. 



Mr. Crossland notes in the Red Sea the close resemblance in form and movement of 

 certain tropical Opheliidae to Amphioxus, and they are abundantly dredged in the same 

 localities. 



The Opheliida3 generally frequent stretches of pure sand, though Ammotrypane is 



1 f Arch, f. mikros. Anat./ Bd. xxi, pp. 769-823, PI. xxxii, xxxiii. 



2 'Arch. Zool. exper./ 3 ser., vol. iv, p. 166. 



3 < Proc. Roy. Soc./ No. 142, 1873. 



4 ' Jenaische Zeitschr./ Bd. xxviii, p. 247, taf. 16-19. 



5 ' Zool. Anzeiger/ Bd. xxii, p. 417. 



6 c Arch. f. Entwicklungsmechanik/ Bd. xviii, p. 161, 13 text-figs. 



