Reptantia:  Crawling Crustaceans

Reptantia Crustacea:  Suborder of the Order Decapoda: walking demersal decapod crustacean, e.g. European Lobster.
This suborder has been discontinued because of changes in the classification, but it will still be found in the old books and even in university marine biology courses.
True Lobster Homaus gammarus is now to be found classified in the Infraorder Astacidea.

New Crustacean Taxonomy (abridged)
 
 

Taxonomy:

Order Decapoda of the subphylum Crustacea of the Arthropoda

Infraorders:

Caridae  (Natantia):  swimming forms like shrimps and prawns (pics).
Thalassinidae:   burrowing prawns.
Astacidea:  true lobsters, scampi.
Palinura:  crawfish, slipper lobsters.
Anomura:  hermit crabs, squat lobsters, porcelain crabs.
Brachyura: true crabs including spider crabs.

e.g.

Order DECAPODA Latreille, 1803 Suborder BRACHYURA Latreillie, 1803
Section DROMIACEA De Haan, 1833 Superfamily DROMIOIDEA De Haan, 1833 Family DROMIIDAE De Haan, 1833
Genus Dromia Weber, 1795
Species Dromia personata (Linnaeus, 1758)

Refs:  Shallow-water Crabs  by R.W.Ingle (Field Studies Council) ISBN  1 85153 258 7
          An Introduction to the Classification of Animals  by C J Lerwill  (Constable 1971)  ISBN 0 09 457700

Lobster:
 
 

Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Pleocyemata  (=Decapoda)
Infraorder:	Astacidae
Family:	Nephropidae
Genus:	Homarus

"Are species real?

"Where we have sexual reproduction a species can be objectively defined as a group of organisms which
reproduce sexually amongst themselves but don't reproduce with members of other species.
Where we don't have sexual reproduction - as in asexual species, or in fossils where we have no idea how
they reproduced - then there is no objective definition of the species just because like the genus, the family
or the class, it's subject to arbitrary human decision."

from:

Evolution
By Mark Ridley
Blackwell Science 1996
CD-ROM

This CD-ROM is based on the best selling book of the same name and covers all the major themes of evolution using text descriptions, illustrations, animated pictures, and video clips.

The Timeline part of the CD-ROM is a particularly interesting brief summary of the evolution of life on Earth.