496 ABICIULE. 



bearing masses exhibit the same relation to the tube as in Nereis, and they occupy the 

 floor of each segment. The areolated tissue in which the ova are contained is distinguishable, 

 he states, into two parts, one of which is densely and intimately connected with the blood- 

 vessels, the other forming a mere utricular receptacle for the generative elements. 



The second division of Levinsen's x Syllidiformia contains six families, viz., Spionidse, 

 ChaetopteridaB, Cirratulidse, Ariciidaa, Chlorgeniidge (?), and Ophelidse (?) They are termed 

 the Syllidiformia spionina. This arrangement might be improved, as also might Benham's 

 view that the family lies between the Sphserodoridas and Typhloscolecidse of his sub-order 

 Nereidiformia. 



Kinberg describes the Ariciea as devoid of jaws, pharyngeal papillae near the margin 

 of the mouth small or obsolete, tentacles, antennae, and palpi absent or minute, no eyes, 

 cephalic lobe conical, terminal ; buccal segment devoid of feet ; tentacular cirri two or 

 none ; a change in the structure of the segments ; branchiae cirrose, dorsal, absent from 

 the anterior segments ; setaa numerous, capillary and annulate. He considered the 

 dorsal cirrus a second branchia, whilst a third was at the extremity of the dorsal division 

 of the foot, and a fourth a papilla near the ventral division. He arranged the genera 

 according to the presence of cephalic appendages — Arioia having four ; by the tentacular 

 cirri, the position of the branchiae, and the condition of the bristles. His uncertainty on 

 the subject is further shown by his separating Anthostoma of Schmarda as a distinct 

 family. 2 



De Quatrefages (1865), like others, separated the Ariciidae from Auclouin and Milne 

 Edwards' group, containing Aonia, Ophelia, and Cirratulus, as a separate family, and 

 arranged them in two great divisions according to the nature of the proboscis, sub- 

 dividing the first series by the structure of the feet, the bristles, tentacles, and caruncle. 



Cunningham 3 says: " In the Ariciidae I need only confirm the account given by 

 Mcintosh, that in the middle of the body the nerve-cords are thrust inwards by the great 

 ventral longitudinal muscles, which contain between them a narrow lamina preserving the 

 connection between the nerve-cords and the epidermis. A single median neural canal 

 runs above the nerve-cords as in Nerine." 



In regard to organs of sense, pairs of otoliths were described by Bobretzky 4 in Arlcia 

 capsulifera of the Black Sea in certain segments behind the third, and in Aricia (Erstedi, 

 Claparede, 5 by Marion and Bobretzky 6 at Marseilles, a form with six pairs of otocysts. 

 Langerhans 7 further mentions in A. acustica similar organs situated dorsally in segments 

 eight to eleven, and, as Fauvel points out, dorsal to the feet, whereas the ciliated organs 

 are ventral to the dorsal division. The latter author 8 has recently found in Scoloplos 

 armiger an otocyst containing grains of quartz in connection with the external ciliated 



1 ' Vidensk. Meddel. Kjobenliavn/ p. 180, etc., 1883. 



2 ' Ofvers. af K. Yet.-Akad. Fork/ No. 9, 1866, p. 337. 



3 'Quart. Journ. Micros. Sc./ vol. 28, p. 273, 1888. 



4 'Black Sea Annel/ (Not seen.) 



5 < Glanures Zoot./ p. 42. 



6 'Ann. Sc. nat./ 6 e ser., t. ii, p. 68. 



7 'Zeitschr. f. wiss. Zool./ Bel. xxxiv, p. 88, Taf. iv, figs. 1—9. 



8 ' Ann. Sc. nat./ 9 e ser., t. vi, pp. 17—25, text-figs, iv and v, pi. iii, figs. 19 and 20, 1907. 



