PROCEEDINGS OF THE NATIONAL, MUSEUM 



VOL. 73 



areas bears one or two retinacula. (Fig. 3c?.) The retinacula are 

 about 30/i, long ; their broadened basal part is surrounded by a circular 

 groove at the place where they are attached to the cuticle. The apical 

 part of the retinacula bears 5 to 10 spindle-shaped excrescences of 

 about 15/x length, which are provided with small lateral barbs. (Fig. 

 3 O^h.) 



In the material of the United States National Museum DrepaTwr- 

 chis ocoidentcdw occurs on the following hosts: 



Macrocoeloma cmnptocerwn (Stimpson) ; of Florida. 



Macrooroeloma diplacanthum (Stimpson) 



ins deferens 

 mantle 

 testis 



chitimus 



visceral 

 mass 



Cuba. 



Microphrys hicor- 

 nut'us (Latreille) ; off 

 Florida ; Cuba ; Ba- 

 hamas. 



Mithrax forceps. 

 (Herbst) ; Bahamas. 



Mithrax forceps (A. 

 Milne-Edwards) ; west 

 coast of Florida. (Host 

 of type.) 



Mithrax sculptus 

 (Lamarck) ; Jamaica. 



Pitho a/nisodon (von 

 Martens) ; off Florida. 



Pitho Ihermdnieri 

 Schramm ; Key West 

 or west coast of 

 Florida. 



Stenodonops furcata 

 coelata (Milne-Ed- 

 wards) ; off Florida. 

 Among these crabs the species of the genera Macrocoeloma^ Mi- 

 crophrys^ and Mithrax belong to the family Periceridse, and the 

 family Majidse is represented by the genera Pitho and Stenodonops. 



LOXOTHYLACUS, new genus 



cclleteric 

 gfloful 



mantle 



cavity 



with. 



Fig. 2. — Dkepanokchis occidentalis from Mithrax 

 FORCEPS (A. Milne-Edwards), longitudinal section, 

 X 30 



Body laterally compressed, mantle opening opposite the stalk. 

 Visceral mass attached to the mantle at some distance from the stalk. 

 Mesentery thin, extending from the place where the visceral mass is 

 united with the mantle to the mantle opening. Colleteric glands 

 with a number of branched tubes, in or near the central part of the 

 lateral surfaces of the visceral mass. Testes curved, the convex part 

 running along the mesentery. 



