ON THE ANTHRACARID^. 137 



the entire limb, i. e., at least the first and second joints ; the third Joint could not have been of 

 large size, a feature distiuguishiug the Eryouidii? as well as Astacidie and the higher Macrurans 

 in general. The first and fifth pair seem to be of about the same size; the third and fourth pair 

 of legs are a little larger than the others and but little longer than the width of the carapace. It 

 is untortunate that no specimens have yet been found with the first pair of limbs entire, but the 

 fact that the two basal and perhaps the third joints are no larger than those of the other pairs of 

 feet indicates that this form differed from all the fossil and recent Eryonidae, and is a character of 

 so much importance as to forbid our regardinsi' Anthrapahemon as a member of that family; the 

 only other alternative being to consider it as a type of a distinct family. Of the four hinder pairs 

 of legs the three terminal joints of the limbs (these affording the diagnostic characters) are pre- 

 served, and the proportions are much as in the four hinder pairs of thoracic legs of the existing 

 deep-sea Pentacheles; of the three joints the proximal and middle ones ai'e long and slender, the 

 inner one longer than the outer of the two; the distal (terminal) joint is rather short and pointed, 

 and apparently chelate. Meek and Worthen remark that the legs are nordivided; whether they 

 meant that the legs are not divided as in the Schizoi)oda, or simply referred to the terminal joint 

 alone, does not appear, but in the specimen before us (No. 20()/?/j) the last joint appears to be 

 chelate, since what seems to be the smaller inner finger is partly but tolerably well preserved, the 

 crust or derm itself being preserved. Yet we may be mistaken.* lu Meek and Wortheu's figure, 

 the terminal joints are drawn as undivided. If this is the case, they resemble the four hinder 

 legs of Munida, Eumunida, and Anoplotes. 



The abdomen is rather short and broad, as in the Galatheidie, and consists of seven segments, 

 counting the telson as the seventh. 



The general appearance and relative size of the telson, together with the last pair of abdominal 

 appendages, is much as in the Eryonidie, with some important differences. The telson, unlike that 

 of any other Macruran, fossil or recent, so far as I am aware, is differentiated iuto three portions; 

 the basal central piece is somewhat polygonal, a little longer than broad ; it is separated by a 

 distinct suture froui a small triangular terminal ])iece which forms the apex of the telson. Between 

 the outer Iialf of the entire telson and the inner ramus of the uropoda is a large broad lobe which 

 is fringed with set;e. At first I regarded it as a subdivision of the inner lobe of the last uropoda or 

 abdominal feet, but no instance among the Decapoda is known to us in which the last pair of 

 uropoda have more thau two lobes or divisions, and I have therefore been inclined to associate the 

 innermost of the three setiferous lobes with the telson, and to regard the telson as divided into 

 two median and two lateral lobular setiferous portions. Whether the two lobes belong with the 

 telson or uropoda I will leave for the present an oi)en question. The only group in existence in 

 which the telson is so remarkably differentiated is the Galatheidie. In Munida the telson is 

 divided by sutures into four pieces, the two terminal ones lobate and edged with setai of the same 

 size as those of the uropoda. In Eumunida of Smith the telson is "short and broad, more or 

 less membranaceous, and divided by a transverse articulation, so that the distal part may be 

 folded beneath the basal part." In Anoplotm politus. like the foregoing, a deep-sea Galatheid, 

 ''tbe telson is stiffened by eight distinct calcified plates; a broad median basal plate, with a small 

 one on either side at the base of tlie uropod, and a small median one behind it, and between a pair 

 of broad lateral plates, still behind which there is a second pair, which meet in the uiiddle line and 

 form the tips and lateral angles." Professor Smith's figures of Munida, Eumunida, and Anopotus 

 are here rei)r(Kluceil from electrotypes kindly loaned by Professor Baird, U. S. Fish Commission. t 



From the nature of theditierentiation of the telson in the Galatheidte I am inclined to believe 

 that the telson of Authrapahemon is subdivided in somewhat the same manner. If so, we cannot 

 refer the genus to the Eryonida', and we would therefore regard it as the type of a distinct family 

 which may thus be briefly characterized : 



Family Anthracaridw : Body rather broad and slightly flattened ; first antennae with two long 



* In none of the six Scottish Carboniferous species of AntUrapaUeraon described by Mr. B. N. Peach, do either of 

 the thoracic limbs appear to be chelate. 



t PreUmiuary report ou the lirachyura aud Aaomura dredged in deep water o6f the south coast of Now England, 

 by the U. S. Fish Commission, in 1?J80. By S. I. Smith, Proc. U. S. Nat. Museum, 1883, June 18. 

 S. Mis. 154 IS 



