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

Explain catastrophism, Catastrophism Once-popular belief which events in t...

Catastrophism Once-popular belief which events in the history of earth had occurred in the past a sudden events and by processes different from those operating today. The periods

Mycotic aneurysms, They result from septic embolization of vegetations to t...

They result from septic embolization of vegetations to the arterial vasa vasorum or the intraluminal space, with subsequent spread of infection through the intima and outward throu

Tiny fraction of this water which is retained by the plant, Most of the wat...

Most of the water taken up by a plant passes through it and is evaporated to the atmosphere. What use is made of the tiny fraction of this water which is retained by the plant?

What is inflammation, What is inflammation? Inflammation is the initial...

What is inflammation? Inflammation is the initial response of the unspecific defense system versus aggressions against the body (the aggressions might be caused by infectious p

Stereochemistry of amino acids - optical properties, Stereochemistry of Ami...

Stereochemistry of Amino Acids: Optical Properties All  amino acids (except glycine) rotate the plane of polarized light because of  the presence of an asymmetric center at C-2

Enteric infectious viral disease, Match each item in Column A with the corr...

Match each item in Column A with the corresponding item in Column B regarding infectious diseases Column A Column B a. Pulmonary tuberculosis i. Enteric infectious protozoan diseas

Agro industrial-selenium, Selenium Glutathione peroxidase (GSH-Px) was...

Selenium Glutathione peroxidase (GSH-Px) was the first selenium metalloenzyme identified.Glutathione peroxidase catalyzes the reduction of hydrogen peroxide and lipid h yp r o

Determine about the nervous tissues, Determine about the nervous tissues ...

Determine about the nervous tissues The nervous tissues throughout the body, including the visual nervous system, are continuously active. Electrical reactions can only be indu

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