Sauer: Morphology Physiology and Behavioral Biology of Ticks

Format: Hardcover

Language: English

Format: PDF / Kindle / ePub

Size: 5.29 MB

Downloadable formats: PDF

These swimming decapods have phyllo- branchiate gills. Zooids usually hermaphroditic, but some con- tain males and females in a single colony; gametes usually arise from transient patches of germinal tissue on peritoneum or funiculus 8. During the Cretaceous period, some plants began to reproduce using flowers. Circulation and Gas Exchange A major aspect of the arthropod bauplan is reflected in the nature of the circulatory system.

Continue reading

Changing Global Perspectives on Horseshoe Crab Biology,

Format: Hardcover

Language: English

Format: PDF / Kindle / ePub

Size: 5.06 MB

Downloadable formats: PDF

Pelagia noc- tiluca, an open-sea diurnal migrator, follows the other migrating macrozooplankton upon which it feeds. You're all behaving like a bunch of animals. When this occurs, the hydroids are said to be thecate; hydroids whose perisarcs do not extend around the zooids are athecate. These phe- nomena may be viewed as developmental evidence of relatedness through shared ancestry, and thus they are examples of “recapitulation” in a broad sense.

Continue reading

Interesting Invertebrates (Creatures of the Deep)

Format: Hardcover

Language: English

Format: PDF / Kindle / ePub

Size: 11.43 MB

Downloadable formats: PDF

Ribosomal DNA phylogeny of the major extant arthropod classes and the evolution of myriapods. The “micromeres” divide rapidly and develop flagella that extend into the embryo’s cavity. Although the phylum Porifera is characterized by fil- ter feeding, members of the demosponge family Clado- rhizidae display an entirely different and unique mode of feeding. Our mammal specimens have also played an integral role in such NMNH exhibitions as The Kenneth E.

Continue reading

Earthworms

Format: Paperback

Language:

Format: PDF / Kindle / ePub

Size: 11.06 MB

Downloadable formats: PDF

Many authors continue to support the “monophyletic theory” that derives the pro- tostomes and deuterostomes from a common triploblas- tic, coelomate ancestor. This similarity is immediately obvious, for example, in features such as symmetry, a gelatinous mesenchyme or collenchyme (formed from ectomesoderm), the absence of a body cavity between the gut and the body wall, and a relatively simple, netlike nervous system.

Continue reading

Zoological Catalogue of Australia (Zoological Catalogue of

Format: Hardcover

Language: English

Format: PDF / Kindle / ePub

Size: 8.35 MB

Downloadable formats: PDF

Specimens are available for loan, on-site research, educational use, artistic reference, and exhibit use. However, many turbellarian flatworms bear a midventral mouth (derived from the blastopore). The exquisite Orsten arthropod fossils show little or no signs of decomposition, and they preserve de- tails less than a micrometer in size (e.g., cuticular pores and setae). Although they possessed stereom ossicles, they were not radially symmetrical, and the nature of their water vascular system (if they had one) is uncertain.

Continue reading

Animals without backbones;: An introduction to the

Format: Paperback

Language: English

Format: PDF / Kindle / ePub

Size: 9.50 MB

Downloadable formats: PDF

Corroboration of this proposal will come from additional embryologi- cal studies that confirm the mesodermal origin of the rhynchocoel. In some species of free-spawning asteroids the females release pheromones that attract the sperm from nearby conspe- cific males (Miller 1989). The stride lengths of the legs overlap some- what and vary with speed and direction of movement. In recent years, deep-sea invertebrates collected by submersible became a focus of our non-mollusk holdings. Most millipedes are slow-moving detritivores with a preference for dead and decaying plant material.

Continue reading

Crustacea Rhizocephala (Marine Invertebrates of Scandinavia)

Format: Paperback

Language: English

Format: PDF / Kindle / ePub

Size: 10.11 MB

Downloadable formats: PDF

Stenolaemates have evolved a mechanism of lophophore protraction unique among the ectoprocts. Tasmania also has its share of impacted systems (heavy metals, human-induced salinity, introduced species). To accept cookies from this site, use the Back button and accept the cookie. After the beaver dam is built and an impoundment (pond) of water forms behind it, lentic (slow-water) invertebrates replace the lotic invertebrates. Males that are in association with females tend to remain male for a relatively long period of time.

Continue reading

Advances in Trematode Biology

Format: Hardcover

Language: English

Format: PDF / Kindle / ePub

Size: 6.07 MB

Downloadable formats: PDF

The structural features associated with this mechanism comprise a synapomorphy on which this group was es- tablished as a separate class. Infraclass Cirripedia Primitively with tagmata as in the class, but in most groups the adult body is modified for sessile or parasitic life; thorax of six segments with paired biramous ap- pendages; abdomen without limbs; telson absent in most, although caudal rami persist on abdomen in some; nauplius larva with frontolateral horns; unique, “bivalved” cypris larva; adult carapace “bivalved” (folded) or forming fleshy mantle; first thoracomere often fused with cephalon and bearing maxilliped-like oral appendages; female gonopores near bases of first thoracic limbs, male gonopore on median penis on last thoracic or first abdominal segment; compound eyes lost in adults (Figures 16.1I, M, 16.16A–E, 16.25, 16.26, 16.27B–C, 16.32E, 16.33E).

Continue reading

Polychaetes: An Interactive Identification Guide

Format: CD-ROM

Language: English

Format: PDF / Kindle / ePub

Size: 9.08 MB

Downloadable formats: PDF

Body spheri- cal but bilateral, jelly-like, with complexly arranged surface cil- iary bands; gut U-shaped; coeloms poorly developed; mono- specific (Planctosphaera pelagica); worldwide; probably a larval stage of unknown adult hemichordate, perhaps an enterop- neust. Between these two epithelial sheets is a mesenchymal layer of stellate ameboid cells embedded in a supportive gel matrix. There is considerable circumstantial evidence that at least some invertebrates are capable of directly sensing differences in environmental temperatures, but actual receptor units are for the most part unidentified.

Continue reading

Microscopic Anatomy of Invertebrates, Echinodermata (Volume

Format: Hardcover

Language: English

Format: PDF / Kindle / ePub

Size: 12.30 MB

Downloadable formats: PDF

Most nematocysts contain several different toxins that vary in activity and strength, but as a class of chem- icals they are all potent biological poisons capable of subduing large, active prey, including fish. The most complex rhizocephalan life cycle is that of the suborder Kentrogonida, obligate par- asites of decapods. Restated, animals have an embryogeny because of their evolutionary histo- ry. Each sporozoite grows into a gamont (2); the gamonts subsequently mate (3–4), becoming enclosed within a mating cyst, which leaves the host with the feces.

Continue reading