654 ARTHROPODA SUB-KINGDOM VII 
these are compared by Woodward with the gastric teeth of the lobster 
(Fig. 1369). 
Sub-Order A. NEBALIINA. Clarke. 
Curapace folded, univalved, and rostrate. 
Family 1. Nebaliidae. Baird. 
Cephalic appendages five, thoracic eight, abdominal eight, terminating in two caudal 
spines. No metamorphosis ; development direct. 

Fic. 1369. 
Gastric teeth of Lchinocaris Fic. 1370 
punctata, Hall. Hamilton; eae 
Pratt’s Falls, New York, 1/}. Nebalia Geoffroyi, M. Edw. Recent; Mediterranean. 8/3. 
Nebalia, Leach (Fig. 1370). Represented by a few species inhabiting shallow 
waters of northern seas. Paranebalia and Nebaliopsis are also Recent and marine. 
Sub-Order B. HYMENOCARINA. Clarke. 
Nebalia-like forms with folded univalved carapace ; rostrum wanting (2). 
Family 1. Hymenocaridae. Salter. 
Body with eight to nine thoracie and abdominul segments, and six caudal spines in 
three patrs. 
Hymenocaris, Salter (Fig. 1371). Carapace narrow 
in front, very broad posteriorly, convex ; surface smooth 
or faintly lined. Cambrian ; Wales. 
[Ribetria, Sharpe. Arched, univalved bodies with 
strong beaks, muscular scars and sub-cardinal ridge. 
These fossils have been referred to the Phyllocarida, 
Pelecypoda, and Gastropoda. There is no satisfactory 
evidence of their Crustacean nature. | 

| Ried Sub-Order C. CERATIOCARINA. Clarke. 
Hymenocaris vermicauda, Salter. ma 5h . BB, hs f iP 
Upper Cambrian; Dolgelly, Wales. Carapace bivalved, with a median symphysis and a 
(after Salter). 1. free rostrum. 
Family 1. Ceratiocaridae. Salter. 
Curapace pod-shaped, smooth, and without eye-nodes. 
Ceratiocaris, M‘Coy (Entomocaris, Whitf.), (Fig. 1372). Valves of carapace elongate, 
sub-ovate, or sub-quadrate, narrow in front, sub-truncate, but not incurved behind. 
a 
