CARINELLA ANNULATA. 205 



paler than the upper. The ventral aspect of the snout has a white patch continuous 

 with, but narrower than, that on the dorsum. The only other markings on this surface are 

 caused by certain pale lines and the circular white belts ; but in a characteristic variety a 

 median white stripe passes along the entire belly from tip to tip. The space behind the first 

 white circle is usually paler than the rest. In a very large dark specimen, sent from Montrose 

 by Dr. How den, the white stripes anteriorly had a beautiful rose-pink shade. Pale red examples 

 from fissures of rocks, when placed in glass vessels, gradually become brownish-red or quite 

 brown by exposure to light. 



Head. — Horseshoe shaped, wider than the rest of the body, not much flattened, and with- 

 out eye-specks. Posteriorly it is gradually narrowed to the cephalic furrows, where a slight 

 shoulder occurs. There is a curved streak in the bend of each ciliated furrow on the dorsum, 

 perhaps in connection with the cephalic sac. These furrows are continued straight inwards on 

 the ventral surface, so as to meet just at the anterior part of the mouth. The latter forms a longi- 

 tudinal slit somewhat less distinct than in Linens. 



A well-marked southern variety occurs in the island of Herm. The head is peculiarly 

 flattened, larger in proportion than in the common form, and pale at the tip. At first sight the 

 body appears to be dull orange throughout, but minute inspection shows a pale lateral line on 

 each side, with a series of minute pale spots above it, and traces of faint transverse bars on 

 the dorsum. 



This species, one of the most handsome and graceful of the whole order, lives a long 

 period in confinement, constructing on the bottom and sides of the vessel numerous hyaline 

 transparent tubes, in which it lies either doubled or coiled in various ways. The tube or case 

 has a fine silky lustre or iridescence, appearing under a high power as an almost structureless 

 membrane with a few minute adherent granules, and irregularly streaked with fine lines, from 

 microscopic folds of the very thin tissue. The animal progresses somewhat slowly ; and though 

 devoid of eyes, it needs but a touch to become aware of the proximity and apparently the nature 

 of any object, so that, for instance, it at once enters head foremost or backs into a tube. Small 

 fragments of the body survive a long time, and move slowly about. In these the anterior 

 end is somewhat pointed. Probably they develop into perfect animals under favourable 

 circumstances. 



The skin gives a marked acid reaction. 



This is another addition to our marine fauna for which we are indebted to the industry and 

 enthusiasm of Col. Montagu. He distinguished the common form and that with the ventral 

 median white line, as well as noticed the white specks at the sides and the broader nature of 

 some of the circular white belts. In the variety with the ventral longitudinal line he states that 

 " the first annulation of white is very close to the anterior end, the second is distant about an 

 inch, and the rest (about 220) are nearly equidistant." The drawing accompanying the manuscript 

 by some accident shows dark instead of white lines on the dorsum. Four succeeding authors of 

 note, viz. Dr. Johnston, Sig. Delle Chiaje, M. de Quatrefages, and Sir J. Dalyell, each described 

 the same animal as a new species. M. de Quatrefages based the distinction of his Valencinia 

 ornata from Col. Montagu's form on the fact that the latter did not note the remarkable enlarge- 

 ment of the head, and because his specimens came from the laminarian region, Montagu's from 

 the coralline. Such data, of course, are unsatisfactory. Moreover, since we observe that a 

 species so prominently barred as Micrura fasciolata occasionally presents none of these charac- 



