Type specimen of class enteropneusta, Biology

Assignment Help:

Q. Type specimen of class enteropneusta?

Examine the specimen and note the following features:

1. Balanoglossus has a soft, elongated, worm-like body which has a ciliated surface.

2. Body length reaches 10-50 cms and is divided into short conical proboscis, , collar and long trunk.

3. Proboscis is cylindrical, tapering and muscular. Near the base is a proboscis pore which is the opening of the coelom (present within the proboscis) to the exterior.

4: Collar is a short, cylindrical, muscular band enclosing a pair of coelomic cavities (collar coelom). The collar opens by a pair of collar pores on the dorsal ; surface. The rim of the collar encloses the mouth which is permanently open. ,

5. The trunk is superficially ringed and divided into 3 parts (a) anterior branchiogenital part containing genital ridge that carry gonads. This part can , be demarcated from the outside as it has gill-slits but the contents cannot be seen without dissection. (b) hepatic region. (c) the posterior end which is the trunk region.

6. The mouth lies at the base of proboscis and is encircled by the edge of the collar.

7. In the hepatic region are present double rows of hepatic caeca.

8. Alimentary canal is straight and anus is at the end of the trunk. (Sexes are separate and fertilization is external. Development includes a free swimming pelagic larva called tornaria larva.)


Related Discussions:- Type specimen of class enteropneusta

What are the main human diseases caused by virus, What are the main human d...

What are the main human diseases caused by virus? Between diseases caused by virus are common cold, flu, mumps, variola (considered eradicated nowadays), rubella, AIDS, measles

Which is the vertebrate class, Q. Which is the vertebrate class that is con...

Q. Which is the vertebrate class that is considered the first entirely terrestrial? Totally independent from the aquatic habitat, The first entirely terrrestrial vertebrate cla

Volvocine Protozoa, Why is Volvocine Protozoa not considered an animal?

Why is Volvocine Protozoa not considered an animal?

To show that growing seeds take in oxygen, To show that growing seeds take ...

To show that growing seeds take in oxygen Cork up one end of a tube, having first placed inside some damp cotton wool and some mustard seeds. Immerse the open end in dilute ca

Bio geographical evidence of evolution, BIO GEOGRAPHICAL EVIDENCE- T...

BIO GEOGRAPHICAL EVIDENCE- The patterns of distribution of animals and plants in different parts of the globe are termed as biogeography. It is believed that around carbo

What proportion of progeny pairs gt or ac have, A haploid cross is made in ...

A haploid cross is made in which the mutant allele has GC at base position 200 in the DNA of a certain gene, and the wild type has AT. What proportion of progeny will have the hybr

Transparency - aquatic habitats, Transparency - Aquatic Habitats Trans...

Transparency - Aquatic Habitats Transparency affects the extent of light penetration. It is indirectly related to turbidity. Suspended particulate matters such as clay, silt a

In vitro fertilisation that involves into the fallopian tub, In vitro ferti...

In vitro fertilisation is a technique that involves transfer of which one of the following into the fallopian tube? 1. Embryo only, upto 8 cell stage 2. Either zygote or ear

Explain idal volume and expiratory reserve volume, Explain the following an...

Explain the following and give their values in a normal human adult: a) Tidal volume b) Expiratory reserve volume c) Inspiratory capacity.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd