﻿HYMENOCARIS VERMICAUDA. 



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Hymenocaris vermicauda occurs in the Lower Lingula-flags, especially " in 

 the upper portions of the true Lingula-flags " (Salter, op. cif., p. 293, and 

 ' Catal. Pal. Foss. Cambridge Mus.,' p. 10), near Tremadoc, Ffestiniog, and 

 Dolgelly. The particular localities 1 are the railway-cutting near Wern, not 

 far from Penmorfa ; Pentre'r-felin, west of Penmorfa ; Gareg-felen ; Bryntwr 

 Summerhouse ; and especially the hill descending to Penmorfa Church j Moel-y- 

 gest, the hill behind Portmadoc ; Borth cove or harbour, near Portmadoc ; 

 also at Ffestiniog; Gwern-y-barcud ('Mem. Geol. Surv.,' vol. iii, p. 294), 

 Moel-hafod-Owen, and other places near Dolgelly; and doubtfully at Pont 

 Seiont, Caernarvon. A specimen in the British Museum is from the ' Upper 

 Tremadoc' schistose shale of Garth, near Portmadoc. The Halifax Museum 

 also possesses one or more specimens from the " Upper Tremadoc flags " of 

 Garth, Portmadoc. 



The rippled flagstones of the Lingula series near Tremadoc, at the village 

 of Y-Felin-newydd, and near Pentre'r-felin and Wern, on the Criccieth road, are 

 marked with tracks referred, with good reason, by Mr. Salter to Hymenocaris 

 vermicauda (' Quart. Journ. Geol. Soc.,' vol. x, 1854, pp. 208 — 211 ; and 'Mem. 

 Geol. Surv.,' vol. iii, p. 248 and p. 294, pi. i). 



§ 1. Carapaces. 



The chief specimens which we have met with and regarded as illustrative of 

 this species are the following : 



1. A large specimen (PI. XIII, fig. 1) wanting the caudal extremity. Both 

 the carapace and the eight abdominal segments have been obliquely squeezed 

 from above and behind towards the infero-anterior region ; and the left-hand 

 carapace-valve here shown is, in particular, somewhat lengthened backwards 

 and downwards. 



This occurs in dark-grey slaty mudstone, minutely micaceous, from the 

 Middle Lingula-flags, at Borth, Portmadoc. In the Cambridge Museum (yfr tsg)- 



It is referred to in the ' Report on British Palaeozoic Phyllopoda ' for 1888 

 (1889), p. 178, fig. 4. 



This is very similar to the specimen figured by Salter in the ' Mem. Geol. 

 Surv.,' vol. iii, 1866, pi. ii, fig. 1, which is in the Museum of Practical Geology, 

 and which lies in dark-grey schistose mudstone from Penmorfa, near Tremadoc. 



2. Carapace and abdomen of a large individual (PI. XIII, fig. 12). Both are 

 imperfect and much compressed. The two valves are indistinctly indicated ; the 



1 Mr. David Homfray, who collected the larger portion of the known specimens of this genus, 

 has favoured us with a note of the localities. 



