26 BRITISH FOSSIL CRUSTACEA. 
of posterior long gnathites, with a large toothed coxopodite, succeeded by a number of 
joints, the last of which has the form of an oval palette. ‘These last members probably 
performed the function of locomotive or swimming feet. A considerable epistomial 
region lies in front of the mouth, as in Zemulus, and a large oval plate, emarginate 
anteriorly, covered the mouth in the median line. 
“No limbs have been found in connection with the abdominal somites, nor have any 
detached parts different from those just described been as yet discovered. Many parts of 
the surface of the body and of the appendages exhibit an exceedingly peculiar structure, 
resembling the conventional representation of feathers, or the mode in which they are 
represented in the Assyrian and Egyptian sculptures ; and it was from this cause, appa- 
rently, that the Scotch quarrymen conferred the title of ‘Seraphim’ upon the Plerygotus. 
“The Diastylide are the only Crustacea with which I am acquainted which exhibit 
anything similar to this ornamentation ; and in the number of free somites, and the more 
or less rudimentary condition of the abdominal appendages, this aberrant group of 
Podophthalmia presents other analogies with the Lurypterida. The carapace, the pre- 
hensile antenne, the largely developed posterior gnathites of Pterygotus, are to be 
paralleled among the Copepoda and Xiphosura, from which, however, and indeed from all 
other adult Crustacea with which I am acquainted, the Hurypterida differ widely in 
certain other respects. 
‘The absence of developed posterior thoracic and abdominal members in a Crustacean 
possessing the corresponding somites is to be met with, in fact, only among the Zoziform 
larvee of the Macrura and Brachyura, in which, as we have seen, the proportions of the 
body are not dissimilar to those of the Hurypterida, where the abdominal appendages are 
entirely absent, and the well-developed and conspicuous thoracic and cephalic members 
are not more than two or three pairs in number, and consist of antennee and maxillipedes, 
the latter serving as locomotive organs. 
“T conceive, therefore, that the Hwrypterida must form a group by themselves, which 
are best understood by combining together organic peculiarities at present found only in 
the Copepoda, the Xiphosura, the Diastylide, and the larvee of Podophthalmia.” 
41. In June, 1858, Mr. J. W. Sanrer communicated to the Geological Society 
descriptions and figures of six new species of Hurypterus, and gave an account of the dis- 
tribution of the group. 
42. On the 22nd January, 1859, appeared Messrs. Huxuny and Saurer’s grand 
Monograph ‘On the Anatomy and Affinities of the Genus Péerygotus, with descriptions 
of twelve species (pp. 105, 8vo, and sixteen folio plates).* 
43. Inthe same year a Russian naturalist, Dr. Jonannes NivszKowsk1,+ published 
* This standard work will necessarily be so frequently referred to in the pages of this Monograph, that 
it would be superfluous to give a mere extract from it here. Its authors are quoted in clauses 26, 36, 37, 
40, 41, 45, 51, and 57. 
+ Dr. Nieszkowski’s paper is referred to by Mr. Salter, ‘Quart. Journ. Geol. Soc.,’ 1863, vol. xix, p. 81 ; 
but the author’s name is misprinted Wieskowski. 
