316 
Dr. Leach's Arrangement of the Crustacea, ^c. 
Mr. C. Prideaux sent me the young of this species from the Ply- 
mouth Sound. 
The fissure in the under part of the orbit is wide enough to ad- 
mit a knife ; in the two following species the sides of the fissure 
touch each other. 
Spec. 3. Portunus emarginatus. 
P. test4 convexiore lineis abbreviatis e granulis compositis, den- 
tibus tribus utrinque ; penultimo minore, fronte emarginato, 
manibus supra unidentatis, unguibus posticis acutis. 
Portunus emarginatus. Leach, Edin. Encycl. vii. 390. 
Habitat ad Danmoniae littora, semel obvius. 
Mus. Nostr. ? . 
Abdomen PCEMiNiE latum, tenuh ciliatum, angustius quam in 
P. Depuratore, articulo penultimo minus arcuato, ultimo an- 
gustiore, acutiore, secundo tertioque minus carinatis, quarto 
vix carinato. 
Spec. 4. Portunus arcuatus. 
P. testd convexiore lineis abbreviatis e granulis compositis, denti- 
bus utrinque tribus ; penultimo minore, fronte arcuato integro, 
manibus supra unidentatis, unguibus posticis acutis. 
Portunus arcuatus. Leach, Edin. Encycl. vii. 390. 
Testae fronte arcuato integro, a Portuno emarginato tantum dif- 
fert ; forte varietas ? 
Habitat in Anglise mari rarifis. 
Mus. Sowerby, Leach. <?• 
** Ungues postici ecostati; palporum geminorum externorum caulis 
interni articulus secundus ad latus internum emarginatus ; orbita 
intern^ sub antennce externa, insertione imperfecta. 
Spec. 5. Portunus marmoreus. 
P. testd, convexA obsolete tenufe granulata, utrinque dentibus quin- 
que 
