NEPHTHTS HOMBERGII. 17 



Ehlers (1868) gives a minute account of the structure of this species, though he did 

 not make out that of the segmental organs. 



V. Grraber * makes the oesophagus of Nephthys caeca one of his types in describing the 

 structure of the region in the annelids, the layers from within outwards consisting of the 

 intima, the pigmented protoplasmic (hypodermic ?) layer, with glands, the subfibrosa, 

 the muscular, and externally the peritoneal. 



Wiren 2 considers, after quoting the descriptions of the feet, that the N. ciliata 

 of Malmgren (1865) is this form, as is also the N. cirrosa and N. ciliata of Ehlers, 

 the N. emarginata of Malm, and the N. longisetosa of Horst. 



Theel's N. Malmgr eni from the Norwegian North Atlantic Exped., 1879, and 

 Hansen's N. atlantica are united by Wiren. 



Mobius 3 was of opinion that this species included N. ciliata, N. Hombergii, and 

 N. incisa, but the finer points of distinction were not considered. Theel 4 was inclined 

 to a similar view, but thought further researches were necessary. 



2. Nephthys' Hombergii, Lamarck, 1818. Plate XLIII, fig. 6; Plate LVII, figs. 6-7 a; 

 Plate LXVI, figs. 4-8— feet ; Plate LXXVIL figs. 2-5— brist. 



Specific Characters. — Head rectangular, more elongated than in N. caeca, tentacles 

 more slender ; posterior pair larger than the anterior (Ehlers) ; inferior tentacular cirrus 

 with its wide base merging into the anterior lip. Body with 130 segments. Proboscis 

 with a slightly longer terminal papilla in the mid-dorsal line. Dorsal lamella broad and 

 low, projecting beyond the tip of the foot; dorsal cirrus short. Branchia (commencing 

 at the fifth foot) large, with a process at its base, and often curved inward; tongue- 

 shaped inner flap guarding base of bristles, and another, somewhat pointed, occurs at 

 the tip of the foot. Lamella of the ventral division large, directed upward and out- 

 ward, broad and truncated toward the tip. Ventral cirrus short and broadly lanceolate. 

 Capillary bristles shorter than in NT. caeca, shafts long with an expanded blade bent down- 

 ward at an angle and tapering somewhat quickly to a delicate point. The edge is finely 

 serrated. The barred (anterior) bristles approach those of N. caeca, the tips perhaps 

 being shorter. Bristles throughout dark. 



Synonyms. 



1555. Scolopendra marina, Rondelet. Insect, et Zooph., in Piscibus Marinis, pt. 2 (Univ. Aquat. 



Hist.), p. 108, fig. I. 

 1818. Nephthys Hombergii, Lamarck. Anim. s. Vert, v, p. 314. 



1 " Die G-ewebe u. Driisen d. Anneliden-CEsophagus," lxvii Bd. der ' Sitz.-ber K. Akad. d. 

 Wiss. ; 1 Abth. Marz.-Heft., 1873, 2 pis. 



2 Chastop, ' Sibirisk och Berings Haf. "Vega" Exped/ Stockholm, 1883. 



3 ' Die zweite dentsch JSTordpol./ 1869-70. 



4 'Kongl. sv. vet. Akad. Handl./ B. 16, p. 24. 



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