[ON THE GAMPSOISTTCHID^. 131 



thick aud Ions; basal joint of eachVere probably attached two slender rami. The entire limbs 

 were about one-half as long as the thoracic legs (see Lacoe's No. 40^"^). There were at least five 

 pairs (and I think traces of a sixth) besides the last pair. The end of the abdomen, with the telson, 

 and last pair of legs are as described and figured by Meek & Worthen. The telson is large iu 

 size, broad and short, somewhat triangular, being broader at the base than at the end. It is some- 

 what spatulate iu form, being well rounded at the end, and much shorter than the inner rami of the 

 appendages associated with it. Its end is fringed with coarsa sctaj. In the last abdominal ap. 

 pendages, the outer ramus is broader than the inner, with a deep longitudinal crease, or impressed 

 line, which fades out on the outer third, or extends to the end of the basal joint. The second, or 

 distal joint, is fringed with fine sette. The suture between the two joints is externally indicated by 

 two setjB larger than the others, and somewhat curved. The inner ramus is somewhat shorter than 

 the outer; the end well rounded, and fringed with set®. It reaches to the second joint of the 

 longer outer ramus. 



Total length of the largest specimen 33°"°. 



Total length of the best preserved specimen 25"™ (Lacoe*8 No. 404«'). This specimen gave us 

 the following measurements : 



Length of Ist antennae (estimated) 8""". 



Length of 2d antenna (estimated) lO-ll"™. 



Length of last thoracic l0g(exopodite) 8"". 



Length of endopodite 4""™. 



Length of telson 3""° ; width 1.5""". 



Length of outer ramus of last pair of abdominal feet 4"™. 



It should be observed that the endopodites are in part represented in Meek and Wortben's 

 figure, but not referred to in their description. They are also partly represented in their copy of 

 Jordan and von Meyer's figure of Oampsonyx fimhriatiis. In the latter, there is also present what is 

 apparently a large, coarsely spined, mandibular palpus, somewhat like that in the male of the exist- 

 ing deep-sea Schizopod Petaloj^hthalmus armatus described by Willemoes-Suhm.* In the females 

 however, the palpus is small and unarmed. In the figure of Gampsonyx referred to, the thoracic 

 legs themselves, irrespective of the endopodites, are represented as biramous, and the two rami are 

 drawn as of neai'ly equal length. It is probable that there has been a mistake in drawing the 

 legs, as iu none of the existing Schizopods, such as Mysis and its allies Euphausia, Guathophausia, 

 Petalopthalmus or Chalaraspis, are the legs thus thrice divided. It is to be hoped that the fossil 

 itself will be examined anew with regard to this important point.t 



It is sufficiently evident, however, that Gampsonyx and Palseocaris are closely allied forms, and 

 as first suggested by Messrs. Meek and Worthen should fall into the same family, which may be 

 called Gampsonychidse. The principal character which separates this group from all other Schizo- 

 pods is the entire absence of a carapace. 



It is worthy of notice, however, that the size of the carapace is very variable in the Schizopods, 

 and in the genus Petalophthalmus there is a great discrepancy in the two sexes. In the female it 

 covers the entire thorax, while in the male it is remarkably small, subtriangular, leaving the two 

 hinder thoracic segments entirely exposed, as well as the sides of the two segments in front. In the 

 large size and oval-lanceolate shape of the endopodites, both of the gnathopods (maxilliiJedes) 

 and thoracicfeet, theGampsouychidae]agree with Petalopthalmus, in which they are large and broad. 

 In the shape of the telson and the comparative size and proportions of the last pair of abdominal 

 appendages there is a close relationshi]) in the Gampsonychidae to the Schizopod genera Petalo- 

 phthalmus and Chalaraspis, especially the latter genus, in which the telson is rounded at the end, 



* On some Atlantic Crustacea from the Challenger Expedition, by Dr. R. von Willemoes-Suhm. Linnasan Trans- 

 actions. Zoology, vol. i, p. 23, 1874. 



tNo light is thrown on the nature of the limbs by the thirty specimens of Palwocaris acoticus described by Mr. 

 B. N. Peach from the lower Carboniferous rocks of Scotland. Nor were eyes with certainty detected in his specimens. 

 " For instance, 'although in most of the specimens there occur small oblong bosses just in the place where their eyes 

 should be, were they decapods, figs. lO-lOrf, yet the facets of the cornea have been looked for in vain. This is unfor- 

 tunate, as it prevents one from saying with certainty that these are the eyes, though there is a strong presumption in 

 favor of their being so. No sessile eyes have been observed on the carapace, neither has a trace of anything been 

 observed that could be construed into such."— Trans. Roy. Soc. Edinburgh, 1882, 'p. 86. 



