34 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 21, 



we have no evidence that the prominent spot (described by M*Coy) 

 on the anterior portion, is an eye, though it is very probable that 

 there are lenses at this point. 



Perhaps there may be no true relation with the Phyllopods in this 

 form any more than in Himantoptej'us -with the Poecilopods. It may 

 be, as Mr. Huxley suggests, also one of the Stomapoda ; and there 

 are some indications of long antennae, which may perhaps, with the 

 apparent absence of abdominal appendages, help to connect it by 

 analogy with some known forms of the group last mentioned. 



In the meantime it is curious to see how gradually we have arrived 

 at our present knowledge of its structure. The carapaces had been 

 known for some time ; but from their resemblance to bivalve shells 

 had lain unnoticed in cabinets. Prof. M'Coy and myself both inde- 

 pendently recognized their Crustacean structure, which he fully pub- 

 lished in his work on the Cambridge fossils ; and he discovered the 

 e3''e, which I had not observed. In the meantime Prof. M'Coy and 

 M. Barrande both recognized the Crustacean character of the tail- 

 spines ; the former distinguishing them from fish-defences *, with 

 which they had been confounded ; and the latter, from better speci- 

 mens, making them out to be the tail, and not the pincers, of an 

 unknown Crustacean. 



In the Dudley limestone the carapace and some of the body-joints 

 were found near together, by Mr. John Gray of that place ; and in 

 the Ludlow Museum, as above noted, are the joints of the abdomen 

 connected with the terminal spines. Lastly, Mr. Slimon's speci- 

 mens show the entire form, and give some hint as to the appendages. 

 It is hoped ere long to illustrate them fully. 



Observations on the Structure «?zc? Affinities o/Himan- 

 TOPTERUS. By T. H. Huxley, Esq., F.R.S. 



From what has been stated in the preceding pages, it would appear 

 that the following propositions embody all that is at present certainly 

 known with regard to the great structural features of the genus 

 Himantopterus. 



1 . The body is composed of a comparatively small carapace, suc- 

 ceeded by eleven or twelve free segments, the last of which is bilobed, 

 lanceolate, or wide anteriorly and acuminated posteriorly. 



2. At the margin of the carapace on each side lies a rounded or 

 oval eminence, which there is every reason to regard as an eye. 



3. The free segments have no appendages. The cephalothorax 

 presents three pairs : an anterior, probably chelate pair, occupying 

 the position of antennae; a middle pair of broad, short, foliaceous, ser- 

 rated organs, which have the appearance of mandibles ; a posterior pair 

 of long flattened, jointed appendages, terminated by an oval palette, and 

 not improbably having an articulated filamentous appendage attached 

 to their penultimate or ante-penultimate joint. 



* Quart. Journ, Geol. Soc. vol. ix. p. 13. 



