6 OPHBLTID^J. 



chitinous (?) thread with spatulate ends passing through their centre — probably con- 

 nected with excretion. 



Attention was drawn by the author in 1875 1 to the interesting resemblances between 

 the structure of the body-wall in this group and in Polygordius (e. g. Lino try 'pane apogon). 



Savigny (1820) mistook the head for the tail of this group, an error corrected by 

 CErsted, though long before the right interpretation was made by Delle Chiaje, Sars, and 

 G. Costa. The relationships were more fully alluded to by Claparede (1868). 



De Blainville 2 included Ophelia along with Aonie and Aglaura in his third order, 

 Homocriciens, and in the section Microceres. No advance was made by this arrangement, 

 and he also described the anterior as the posterior end in Ophelia. 



Audouin and Milne Edw^ards (1834) placed the Opheliidae as one of the genera of 

 their " Ariciens," under which they also ranged the Ariciidae, the Cirratulidae, and certain 

 Spionidae. In their remarks on Ophelia they correctly demur to the view of Savigny that 

 antennae (tentacles) are present, but they describe the proboscis as provided with thirteen 

 or fourteen tentacles, whereas, so far as can be observed, the margin is only frilled in 

 perfect examples. They also interpreted the dorsal cirrus as a ventral one. On the whole, 

 they thought the organisation of the group so peculiar that it nearly approached the 

 Terricolous annelids. 



In his original description H. Rathke (1843) compared the glistening elastic skin of 

 the Opheliidae with that of the Nematoids and Nereids. 



The first family under Grube's second Tribe Limivora (1851) was the Opheliacea, and 

 he associated Scalibregma with Ophelia, Ammotrypane, Travisia, and Eumenia. 



De Quatrefages (1865) placed this family after the Scalibregmidae, and was inclined 

 to think the type intermediate between the errant and the sedentary annelids, approaching 

 the Arenicolidae on the one hand and the Ariciidae on the other. Moreover, he made a 

 distinct family for the Polyophthalmea, which he relegated to the errant annelids — after 

 the Glyceridao, at the end of the series ; yet he pointed out certain affinities with the 

 Arenicolidae. He was impressed by the occurrence of pigment-spots (eyes) on the head 

 and along the body, and named the group accordingly. The digestive system of the 

 Polyophthalmea presents a large buccal chamber, proboscis, a convoluted oesophagus, and 

 a moniliform intestine, the whole being confined to the dorsal half of the ccelom by a 

 muscular platform, beneath which are the reproductive elements. The circulatory system 

 shows a heart of three chambers analogous to that in Arenicola. The respiration is 

 probably cutaneous and rectal. He thought the secretory apparatus was represented by 

 two " salivary " glands beneath and at the sides of the intestine anteriorly. The other 

 structures were normal. The Opheliidae were arranged according to the distribution of 

 the branchiae, Ophelia and Travisia having these only in the middle region of the body, 

 whereas Branchioscolex had many branchiae. The author does not mention Armandia, 

 Filippi. 



In the ' Schlesische Gesellschaft ' for 1869 Grube reviews this family, and points out 

 that the presence or absence of gills is an important feature. Thus : 



(1) Without branchiae — Ex. Polyophthalmus. 



(2) With branchiae or cirri in all the genera. 



1 ' Ann. Nat. Hist./ ser. 4, vol. xvi ; p. 369, with 2 text-figs. 



2 < Diet. Sc. nat./ t. 57, p. 479. 



