Carinella sentence example
- One of them is found in the two most primitively organized genera, Carinella and Cephalothrix, i.e.
- In Carinella, Cephalothrix and Polia, as well as in all Metanemertines, the basement membrane of the skin already alluded to is particularly strong and immediately applied upon the muscular layers.
- In Carinella this separation into lobes of the anterior thickenings of the cords has not yet commenced, the ventral commissure at the same time being extremely bulky.
- In Carinella, where the longitudinal nerve-stems are situated exteriorly to the muscular layers, this plexus, although present, is much less dense, and can more fitly be compared to a network with wide meshes.
- It stretches forward as far as the brain, and in Carinella is again continued in front of it, whereas in the Heteronemertines the innervation of the anterior extremity of the head, in front of the brain, takes the form of more definite and less numerous branching stems. The presence of this plexus in connexion with the central stems, sending out nervous filaments amongst the muscles, explains the absence, in Pro-, Mesoand Heteronemertines, of separate and distinct peripheral nerve stems springing from the central stems innervating the different organs and body-regions, the only exceptions being the L.N.Advertisement
- As to the Mesonemertini, in the most primitive genus, Carinella, we do not find any lateral organs answering to the description above given.
- Only in one species, Carinella inexpectata, a step in advance has been made, in so far as in connexion with the furrow just mentioned, which is here also somewhat more complicated in its arrangement, a ciliated tube leads into the brain, there to end blindly amidst the nervecells.
- Two lateral, shallow pits occur on the side of the body about the level of the hinder end of the proboscis in some species of the genus Carinella, which are termed side-organs.
- In the Metanemertines it is generally situated towards the middle of a lateral transverse groove on either side of the head, as was noticed for Carinella, and as is also present in Polia.
- In Carinella they are generally deficient and the intestine straight; in young specimens of this species, however, they occur, though less regular and more in the form of incipient foldings by which the digestive surface is, increased.Advertisement
- The circulatory system of Carinella is considerably different, being more lacunar and less restricted to definite vascular channels.
- - Diagrammatic sections to show disposition of internal organs in Carinella (Protonemertini), fig.