260 //. Woodwai'd — New Fossil Crustacea. 



Having lately obtained from the Gault of Folkestone the beautiful 

 crustacean figured on Plate XIV. Fig. 4, I at first inclined to con- 

 sider it a new species ; but after a very careful comparison of it 

 with Professor Bell's N. tricarinaius, I am led to conclude that it 

 is only a more perfectly preserved specimen of that species than 

 has been hitherto met with. It is, however, extremely valuable, 

 as serving not only to complete the necessarily im23erfect descrip- 

 tion of the species, but also to demonstrate that, in all probability, 

 its affinities are with the Portunidce, and not with the Corysiidce. 

 But, on this point, however, we still need fuller evidence than that 

 to be derived from the form of the carapace, of which, as yet, only 

 the uj^per surface is known to us. 



Description. — The specimen figured on our Plate measures If inch in greatest 

 breadth, and 1^ inch in length. The posterior margin is 8 lines in breadth and expands 

 ■with a nearly straight border laterally to the epibranchial spine, where it is If inch 

 broad. The latero-anterior border is rounded and is marked by 4 spines, in addition 

 to the epibranchial spine. The orbits have two fissures in their superior margin. The 

 nuchal furrow is distinctly marked and is divided into two branches, laterally, en- 

 closing the hepatic region. Behind the nuchal furrow and separating the urogastric 

 from the epicardiac lobe is a short, strongly-marked transverse cardiac furrow, 3 lines 

 in length, which indents the median ridge or carina, and is then bent forward and out- 

 wards for about 2| lines. 



h\ decorticated or water-worn specimens (as in tliose figured by Professor Bell and 

 on the right-hand side of the specimen figured in our Plate (Fig. 4), there is a curved 

 sculptured line between the meso- and ni eta- branchial lobes strongly marked and re- 

 sembling impressed letters. A distinct, but not very elevated, carina follows the median 

 line, extending the Avhole lengtb of the gastric region, and is only interrupted by the 

 cardiac furrow; whilst another less strongly marked granulated ridge marks each 

 branchial region, extending longitudinally on the middle of the meta-branchial lobe. 

 The epigastric and protogastric lobes are marked by tubercles of moderate size ; a 

 somewhat larger and more prominent one is seen on each epibranchial, and three 

 minute prominences mark the epicardiac lobe. 



After a more careful comparison of Professor Bell's Necrocarcinus 

 Becliei and N. Woodioardii with N. tricarinatiis, one cannot but con- 

 clude that the two former species are generically distinct from the 

 latter — i.e., of course assuming that it is lawful to differentiate a fossil 

 species of Crustacean upon the carapace alone, without a knowledge 

 of the other parts. 



The generic name applied to the original species described by 

 Deslongchamps in 1836 (Mem. Soc. Linn. Norm. V. p. 40, t. 1, 

 fig. 7-9), was Orithyia Becliei. The generic name Orithjia ought, 

 therefore, to be re-habilitated for Becliei and Woodwardii, restricting 

 Necrocarcinus to the species tricarinatiis. 



Sir H. T. de la Beche has figured an example of 'Necrocarcinus tri- 

 carinatiis from near Lyme Eegis, Dorset^ (probably from the true 

 Gault). Professor Bell records and figures it from the Upper Green- 

 sand of Cambridge and Wiltshire : the specimen in our plate is 

 from the Gault of Folkestone. We have thus evidence of its oc- 

 currence in four well-marked British localities. 



III. Paliimrina longipes, IMiinst. [Plate XIV. Fig. 5].— In Count 

 Miinster's Beitriigo zur Petrefactenkunde, 1839, JBd. II. p. 36, he 

 proposed the genus Palinurina for certain species of Macroura 



^ Trans. Geol. Soc, 2ud series, Vol. I. pi. iii. fig. 1, p. 42. 



