194 James Carter—On Fossil Isopods. 
To this list may be added Palega McCoyi, the new Cretaceous 
form described in this paper, thus making a total of eight species as 
representing the fossil Isopods in Britain. In Phillips’s Geology of 
Oxford and Valley of the Thames, p. 122 (1871 ed.), the genus 
4iya is mentioned in a list of Liassic fossils, but no specific name, 
figure or description is given. 
In investigating a tribe of genera it is obviously desirable not 
only to consider each genus separately and distinctly, isolated from 
its allies, but also to consider it with reference to other forms, so 
as to determine its relationship and phylogeny, and the precise 
zoological position which it occupies. To do this at all completely 
is as difficult as it is interesting, even with reference to living 
organisms ; but with regard to those which occur only in a fossil, 
and consequently in a more or less imperfect, condition, the difficulty 
is increased ; and in the case of the Isopods—as indeed in that of the 
innumerable host of perishable organisms which doubtless existed in 
geological periods—it is well-nigh hopeless to attempt such an 
enquiry, inasmuch as the supply of material in the shape of speci- 
mens is so extremely limited. It may, however, be useful to give 
collectively a brief epitome of the publications of the few paleeonto- 
logists who have written upon the subject up to the present date. 
In 1879 Dr. H. Woodward, who is well known to have long 
given special attention to, and to have contributed so largely 
towards a knowledge of, fossil carcinology generally, made a 
valuable communication to the Geological Society (Q.J.G.S. vol. 
xxxv.), in which he has given a list of described species of Isopoda, 
including the seven already alluded to as being British, and seven 
foreign ; and has added copious notes and observations. 
Dr. Ludwig von Ammon, of Munich, has published an able and 
exhaustive paper—“ Hin Beitrag zur Kenntniss der fossilen Asseln ” 
(Sitzungsber. d. Math.-Phys. Classe der k. k. Akad. d. Wissensch. 
1882, Heft iv.), in which he has described a new species of 
Palega (P. scrobiculata), and critically reviewed, with abundant 
bibliographical references, the contributions of various authors who 
have written upon Isopods. He has also compiled a_ table, 
systematically and stratigraphically arranged, of all the species 
which he regards as true Isopods, including those which Dr. Wood- 
ward had previously enumerated, and adding the ten following :— 
‘Isopodites triassicus, Picard, Trias. (A doubtful form.) 
Urda rostrata, Munst. Solenhofen, 
>> punctata, 99 D9 
Aigites Kunthi, vy. Ammon ,, 
Palega serobiculata, vy. Ammon, Tertiary. 
From the “ Unter oligocaen,” Tyrol; a large species 
very nearly allied to Palega Carteri, Woodw. 
Oniscus convexus, Koch und Berendt, Tertiary (in Amber). 
Trichoniscus asper, Menge, 4 
Porcellio notatus, Koch und Berendt, a 
»,  granulatus, Menge, 59 
»,  eyclophorus, Menge, 3h 
The five last mentioned are terrestrial Oniscidz, of small size, 
and nearly allied to recent forms. A new Mexican species of 
