OWENIA. 355 



formia, and in this he offends no canon of classification. They are placed after the 

 iMaldanidaB as Malmgren and De Quatrefages did, but instead of being followed by the 

 Hermellidae, as in the former author's arrangement, Levinsen places the Amphictenideo 

 next. His genera are Myriochele and Owenia. 



The Ammocharidse were placed by Benham (1896) under the second sub-order 

 (Spioniformia) of the order Nereidiformia. Their structure, however, does not agree with 

 their surroundings in this position. 



Hacker (1896) 1 considered the Mitraria-larva of Owenia as that of Magelona. Later 

 (1898) 2 he describes and figures two forms from the 'National ' Expedition to the Atlantic, 

 viz. Mitraria slcifera and M. Mulleri, the former with pointed, sabre-like bristles, and the 

 latter with pointed, club-shaped bristles. He does not, however, connect them with a 

 particular family of Polychasts. A remarkable allied type is Eostraria, a form also with 

 long tentacles and several pairs of long, swimming bristles. 



De St. Joseph (1898) thought the group approached the Maldanidas and Serpulidas, 

 especially the former, in their cylindrical body, in the irregularity of the segments, and in 

 the nature of the bristles and the hooks, which in their number, however, approach those 

 of the Serpulidse ; yet the thread-glands are found in neither group. 



Gilson (1898), who has devoted much attention to the structure of Owenia, 

 describes the body-wall as composed of only two coats, an epidermal (without a cuticle) 

 and a musculo-granular. The latter has a layer of gland-cells so intimately associated 

 with it that he is of opinion they are practically continuous. The glandular lining 

 secretes albuminoid substances, fatty bodies, and urea. The former furnishes the 

 spermatic plasma in the male, and in the female floats the eggs and gives them an 

 envelope. Since the nephridia have lost the function of urinary secretion, moreover, it is 

 this glandular coat which takes up that function, and the granules on the dorsal wall are 

 conducted to the genital funnels (transformed nephridia). 



The family of the Ammocharidse forms a comparatively recent introduction into 

 zoological literature, and yet its representatives, though few, are world-wide in their dis- 

 tribution. No mention is made of any species in Dr. Johnston's ' Catalogue of the 

 Non-Parasitical Worms,' though in 1842 Delle Chiaje had described and figured 

 Owenia fusiformis, the common form on the British shores, and which is often tossed in 

 hundreds on the west sands of St. Andrews after storms. The genus Myriochele appears 

 to be more or less a deep sea form, the example procured by the ' Challenger ' being 

 from 2975 fathoms on a bottom of red clay. 



Genus CXXX .— Owenia, 3 Delle Chiaje, 1842, Ammochabes, Grube, 1846. 



Cephalic rim with dichotomously divided branchiae arising from a campanuliform 

 membrane. Body rounded anteriorly, tapered posteriorly, and ending in a papillose 



1 'Zeitschr. f. wiss. Zool./ Bel. Ixii, p. 86. 



2 l Biol. Centralblatt/ Bd. xviii, p. 96, figs, p and G. 



3 Oivenia, as Grube points out, has been used by Kolliker for a Cephalopod and also for one 

 of the Ctenophora. 



