NBPHTHTDID^B. 5 



the cylindrical proboscis with its terminal and lateral papillae and its two maxillae, together 

 with the fusion of the dorsal cirrus and the branchia, and the lamellar (he called it 

 branchial) condition of both divisions of the foot. He adopted a similar arrangement to 

 that of Grrube — placing the Nephthydea between the Nereiclea and Phyllodocea. 



Malmgren first (1865) placed the J^ephthydea (Grube) after the Phyllodocea, but in 

 his later publication (1867) he altered this arrangement, for they come between the 

 Sigalionidae and the Phyllodocidae. The author may have found that their relationships 

 were such that they most naturally occupied this position. 



In his remarks on the general characters De Quatrefages (1865) explains the so- 

 called compound bristles of certain species as the result of partial fractures of these 

 organs, with a proneness to split at an angle to the long axis. He describes the cephalic 

 ganglia as subdivided into a main and three accessory ganglia connected by a seventh 

 ganglion elongated transversely. He finds an ocular apparatus joined with the main mass 

 (cerveau) though there may be no trace of eyes. The oesophageal connectives give the 

 twigs to the rudimentary feet of the buccal segment. He states that instead of one 

 ventral vessel two distinct trunks exist. He divided the group into three divisions, those 

 with four, those with three, and those devoid of antennae (tentacles). The latter division, 

 however, was due to a misapprehension. 



Claparede (1868) emphasises the fact, first pointed out by Ley dig, that the muscular 

 fibre separates into two distinct layers — one axial — the other cortical. This is well seen 

 in JSTephthys. 



A distinct advance on the treatment of the Nephthydidae was made by Ehlers (1868), 

 who corrected and arranged the known facts as well as added to our knowledge of the 

 subject. The segmental organs he did not observe. He divided the family into two 

 genera, viz., those with four tentacles and a single caudal cirrus (Nephthys), and those 

 with two tentacles and two anal cirri (Portelia). The latter genus, however, has no 

 British representative, and considerable confusion has been caused by the inclusion of 

 the well-known N. cxca, 0. Fabricius, under it. In classifying the known species of the 

 genus Nephthys he made use of the length of the posterior lip in each division of the foot. 



Langerhans divided the Nephthydidae into two groups according to the number of 

 longitudinal rows of papillae in the proboscis. The first of these has 14 longitudinal 

 rows of papillae on the proboscis, as in N. Griibei and others. In the second group the 

 proboscis has 22 rows, as in N. cseoa. 



Levinsen l (1883) placed the ISTephthydidae (his Nephthydae) as the second group of 

 his Phyllodociformia, and thus prominently kept up the relationship with that family 

 without associating it with others considerably divergent in structure. 



Pruvot 3 (1885) found in Ne/phthys a stomato -gastric centre (anterior division of the 

 brain), and an antennary centre (middle and posterior divisions). A nuchal organ is 

 present posteriorly. The group agrees with Phyllocloce in this respect. 



1 Viclensk/'Meadel. Nat. Hist. Kjobenhavn, Aaret 1882/ 1883, p. 180. 

 3 < Arch. Zool. Exper/ ser. 2, HI, p. 48-49, 1885. 



