DEVELOPMENT OF THE ANOPLA. 119 



being filled, in addition, with the transparent flasks from which they have escaped, and a few unde- 

 veloped ova. Moreover, it is a common practice for the adults to creep through these masses, 

 and several are generally coiled in proximity. The number of undeveloped ova is extremely small, 

 showing how easy it is to rear these animals, even with very limited supplies of sea-water. 



The young Linei, at the stage previously mentioned, are visible to the naked eye as small 

 elongated worms, somewhat tapered at the ends, pale, or rather translucent in front, and opaque- 

 whitish posteriorly (Plate XXIII, fig. 9), while in structure they now closely approach the adult. 

 The whole surface of the body is richly coated with' cilia, which are especially active in the 

 cephalic fissures, and still more so at the openings of the cephalic sacs. The ganglia are indicated 

 by a pale space (k) on each side, but their actual outline is indistinct. There are in all cases at 

 least two well-marked eyes. The cephalic sacs (m) are large and well defined, indeed very much 

 larger proportionally than they are in the adult ; and from their present position with respect to 

 the ganglia, demonstrate the true form of the latter, as well as the error into which those authors 

 have fallen who have confounded the sacs in the mature animals with posterior ganglionic enlarge- 

 ments. The sacs open by their ducts at the posterior part of the cephalic fissures (£), and the 

 ciliary action can be traced inwards from these points. The oesophageal division (J) of the 

 digestive canal is distinguished by its pallor, more evident ciliation, and the well-defined border of 

 the succeeding opaque region (/). The proboscis (a) is marked by a central streak of papillae, 

 and, after tapering posteriorly, curves forward, and disappears. The proboscidian sheath (o) 

 is banded here and there anteriorly by transverse bridles ; and a clear line is occasionally visible 

 on each side of the opaque alimentary tube, as if from circulatory undulation. An anal papilla 

 (Plate XVII, fig. 22), with a ciliated line connecting it with the digestive cavity, is also apparent. 

 Shortly after reaching the degree of advancement shown in Plate XXIII, fig. 9, the young 

 Linei leave the gelatinous masses, and congregate at the water-line. Hundreds now perish from 

 want of sufficient food, which in their native haunts is probably both abundant and suitable, 

 while in the artificial circumstances and confined vessel it is denied them. Ten weeks 

 afterwards the young animals are found still of the same whitish hue, and possess only 

 two eyes, rarely an additional pigmentary fragment. The proboscis has much increased in 

 size ; indeed, at this time it has attained a comparatively larger development than the digestive 

 cavity, which is in active use, since the young animal is entirely dependent on its own exertions 

 for a supply of food. The oesophageal region is very distinctly marked, though its dimensions are 

 proportionally small when contrasted with the length of the head ; at present it is not a quarter 

 the length of the latter, whereas in the adult it is several times longer. Its space is also con- 

 siderably encroached on by the large cephalic sacs. 



At a further stage of development the animal is much elongated (Plate XXIII, fi.g. 10), yet 

 still possesses only two eyes. In this condition it has been mistaken for the representative of a 

 different genus, and is probably that referred to by Dr. Johnston, under the name of Cephalothrix 

 [Vermiculus Zineatus, Daly ell). 



A vast cord of ova, about a foot long and half an inch in diameter, and which in all pro- 

 bability pertained to Lineus marinus, was brought from the deep-sea fishing off St. Andrews Bay 

 about the end of June. The capsules are arranged in the gelatinous mucus in somewhat 



against different objects, one might suppose it endowed with a certain amount of curiosity; sometimes, 

 also, I saw them shake themselves convulsively, as if they had a chill ." 



