438 



DISCOVERY REPORTS 



The specimens from the east coast of Africa are not distinguishable from the Atlantic 

 specimen. 



Although the oldest of these three specimens is more than twice the size of the smallest 

 one, it diflFers very little in degree of development. The antenna shows a division into 

 flagellum and peduncle, and the latter is 

 rather stout, with a small outer pro- 

 jection (Fig. 42 b). The maxilla is not 

 expanded, and without setae, and max- 

 illipede i is a small papilla. In the speci- 

 men of 20 mm. this appendage is not 

 traceable at all. The abdomen in the two 

 smaller specimens is unsegmented, with- 

 out trace of pleopods, and the uropods 

 are represented in the larger specimen by 

 small folds. In the specimen of 37 mm. 

 the abdomen is still not much more de- 

 veloped, but the pleopods are represented 

 by small simple lobes and the uropods 

 are small and bilobed. 



This form of Phyllosoma is very re- 

 markable by reason of the large size 

 reached without much progress in devel- 

 opment of antennae, mouth parts and 

 abdomen, while leg 5, which is usually 

 late in developing, is fully formed and 

 provided with an exopod in the smallest 

 specimens known. 



Phyllosomas of precisely similar form 

 have been described by Guerin, Richters 

 and Spence Bate. Spence Bate's speci- 

 men, of 30 mm., was taken in the West 

 Indies and may well belong to the same 

 species as the one from St. 691. Phyllo- 

 soma guerini, de Haan, also has an exopod 

 on leg 5, but is otherwise very different. 

 A Phyllosoma from China described by 

 Richters (1873, pi. 34, fig. i) seems to 

 belong to the same genus as P. guerini, 

 and there is reason to believe that this 

 genus may be Ibactis (Balss, 1914, p. 81). 



Richters included the type under discussion in the "Phylicsomes brevicaudes" of 

 Milne-Edwards, and refers them to the Scyllaridae. The general form of the body is so 



4mm 



Fig. 42. Parribacus sp.? 



a. Specimen of 15 mm. St. 691. 



b. Antennae of specimen of 37 mm. St. 1582. 



