Although Haeckel's ideas are important to the history of evolutionary theory, and he was a competent invertebrate anatomist most famous for his work on radiolaria, many speculative concepts that he championed are now considered incorrect.

Although invertebrate embryology is similar in some ways for different invertebrate animals, there are also countless variations.

Although these books are not footnoted in this article, the following are well-illustrated, well-organized — and often well-worn — guides to invertebrate ( and sometimes other ) fossils:

Although the brain is usually cited as the supervisory centre of vertebrate nervous systems, the same term can also be used for the invertebrate central nervous system.

Although invertebrate experts do not necessarily agree on these categorizations, groups that are generally incorporated into Aschelminthes include:

Although most species are associated with water and damp habitats, some are specialised to live in trees and in deserts.

Although in many frog species, females are larger than males, this is not the case in most species where males are actively involved in territorial defence.

Although most extant species of Asteraceae are herbaceous, the examination of the basal members in the family suggests that the common ancestor of the family was an arborescent plant, a tree or shrub, perhaps adapted to dry conditions, radiating from South America.

Although the name actually applies to a group of snakes, it is often used to refer only to one species in particular, the common or green anaconda, Eunectes murinus, which is one of the largest snakes in the world.

Although originally considered a subspecies of A. ramidus, in 2004 anthropologists Yohannes Haile-Selassie, Gen Suwa, and Tim D. White published an article elevating A. kadabba to species level on the basis of newly-discovered teeth from Ethiopia.

Although several species are often considered weeds, people around the world value amaranths as leaf vegetables, cereals, and ornamentals.

Although the family ( Amaranthaceae ) is distinctive, the genus has few distinguishing characters among the 70 species included.

Although there were low levels of preexisting antibiotic-resistant bacteria before the widespread use of antibiotics, evolutionary pressure from their use has played a role in the development of muiltidrug resistance varieties and the spread of resistance between bacterial species.

Although those of many marine species function first as males and then as females, their colonies always contain a combination of zooids that are in their male and female stages.

Although a bee sting can be deadly to those with allergies, virtually all bee species are non-aggressive if undisturbed and many cannot sting at all.

Although not known with certainty the total number of species in the family, conservative estimates indicate approximately 2. 600 species worldwide, distributed in 109 genera.

Although 115 species of fish have been identified in the waters near Clipperton, the only economic activity in the area is tuna fishing.

Although the newborn ibex died shortly after birth due to physical defects in its lungs it is the first time an extinct animal has been cloned, and may open doors for saving endangered and newly extinct species by resurrecting them from frozen tissue.

Although the early embryos of different species exhibit similarities, Haeckel apparently exaggerated these similarities in support of his Recapitulation theory, sometimes known as the Biogenetic Law or " Ontogeny recapitulates phylogeny ".

Although forests are classified primarily by trees, the concept of a forest ecosystem includes additional species ( such as smaller plants, fungi, bacteria, and animals ) as well as physical and chemical processes such as energy flow and nutrient cycling.

Although some recent writers suggest that Homo georgicus was the first and most primitive hominid ever to live outside Africa, many scientists consider H. georgicus to be an early and primitive member of the H. erectus species.

Although human infanticide has been widely studied, the practice has been observed in many other species of the animal kingdom since it was first seriously studied by Yukimaru Sugiyama.

Although the word jackal has been historically used to refer to many small-to medium-sized species of the wolf genus of mammals, Canis, today it most properly and commonly refers to three species: the black-backed jackal and the side-striped jackal of sub-Saharan Africa, and the golden jackal of northern Africa and south-central Eurasia.

Although all sea ducks readily feed on shallow-water molluscs, no Western Atlantic bird species seems to have been as dependent on such food as much as the Labrador Duck.

Although they were not completely unknown to biologists of the time, they were not seen as generally applicable, even by Mendel himself, who thought they only applied to certain categories of species or traits.

Although because of the important achievements of nineteenth century scholars in the field of textual criticism the advance is not so striking as it was in the case of archaeology and place-names, the editorial principles laid down by Stevenson in his great edition of Asser and in his Crawford Charters were a distinct improvement upon those of his predecessors and remain unimproved upon today.

Although the entrance to the chamber warns against disturbing him, Shrewsbury opens Alhazred's sarcophagus anyway, finding that only rags, bones, and dust remain of Alhazred.

Although some of his lands were restored to the control of his relatives, his safe return could not be arranged, and Hasan Ali Shah was forced to remain a permanent resident of India.

Although details remain disputed, the vast majority of recent studies agree with Martin Noth's thesis, published in 1943, that the book of Samuel was composed as part of the Deuteronomistic history, the books of Deuteronomy, Joshua, Judges, Samuel and Kings.

Although the mechanics of ballpoint pens remain relatively unchanged, ink composition has evolved to solve certain problems over the years, resulting in unpredictable sensitivity to light and some extent of fading.

Although the team has been sold to Los Angeles investor Mark Attanasio, questions remain regarding Selig's past involvement.

Although he initially declined the part of Dr. David Banner in The Incredible Hulk because of its comic book origins, on reading Kenneth Johnson's script for the pilot episode, he was persuaded to change his mind ( and agreed to remain involved with the series for as long as Johnson was to be involved ).

Although risks have increased, economic prospects for 2008 remain strong.

Although there are often disputes about its organisation and funding, British parties to this day must still voice their general support for the NHS in order to remain electable.

Although the shooter's motives remain unknown, relatives of the shooter had expressed concerns about his mental health.

Although contemporary electron microscopes are capable of two million-power magnification, as scientific instruments, they remain based upon Ruska ’ s prototype.

Although Salkeld rejected his offer of marriage, she was to remain a friend and regular correspondent for many years.

Although reconstruction has proceeded quickly with significant aid from the international community, tourism and agricultural activities remain weak and nearly offset the stimulus from the reconstruction boom.

Although signs of recovery have been seen in Grenada after the damage inflicted by Hurricanes Ivan and Emily, economic conditions remain difficult ; GDP is projected at a growth rate of only one percent for 2005.

Although unsuccessful, the discussions between the two were instrumental in Boccaccio writing the Genealogia deorum gentilium ; the first edition was completed in 1360 and this would remain one of the key reference works on classical mythology for over 400 years.

Although almost any subject can be found in almost any scale, there are common scales for such miniatures which remain constant today.

Although Albania has made strides toward democratic reform and maintaining the rule of law, serious deficiencies in the electoral code remain to be addressed, as demonstrated in the June 2001 parliamentary elections.

Although relations among different religious and ethnic groups are largely harmonious, acute sectarian discontent and violence remain problems in some areas.

Although Michell seems to have withdrawn from the group when he moved to Leeds in 1767, Franklin was to remain a common link among many of the early members.

Although mimeographs remain more economical and energy-efficient in mid-range quantities, easier-to-use photocopying and offset printing have replaced mimeography almost entirely in developed countries.

Although the details remain sketchy, Kerensky appeared to become frightened by the possibility of a coup and the order was countermanded ( by comparison, historian Richard Pipes has argued that the whole episode was engineered by Kerensky himself ).

Although the major churches are under indigenous leadership, a large number of missionaries remain in the country.

Although insert and delete operations are complicated, their times remain O ( log n ).

Although in modern British usage counties are referred to as " shires " mainly in poetic contexts, terms such as Shire Hall remain common.