Fig. 31. Palinwellus}, \"] mm. 

 Dorsal view of head region. 



426 DISCOVERY REPORTS 



Fore-body about as wide as long, with a small but perfectly distinct sharp-pointed 

 rostrum (Fig. 31). Hind-body much narrower than fore-body, not hollowed behind. 

 Abdomen small, distinctly segmented, with bilobed uropods but no pleopods. 



Antennules with peduncle of two segments, endopod distinct. Antennae with basal 

 part distinct from flagellum and produced outwards into a strong spine. Flagellum 

 nearly reaching end of antennule. 



Maxillule with small papilliform palp. Maxilla 

 with exopod large, extending behind maxillipede 

 2, and fringed with setae. Maxillipede i a small 

 papilla. Maxillipede 2 with exopod of fair size but 

 without setae. Maxillipede 3 having large setose 

 exopod. 



Dactyli of legs short and curved ; each leg with 

 coxal spine and a group of spines at end of merus. 

 Leg 5 about twice as long as abdomen, segmented, 

 with large rudiment of exopod. 



It is unfortunate that only one specimen, and that a young one, of this Phyllosoma is 

 available, since it is a very remarkable form and the last stage might give some clue to its 

 identity. It is unique in having a well-marked rostrum, and the presence of an exopod 

 on leg 5 is another character which is unusual, and perhaps primitive. 



The form of the maxillae, presence of exopods on maxillipedes 2 and 3, and presence 

 of a palp on the maxillule, point with certainty to the Palinuridae, and probably to near 

 relationship to Palimirus ; but it obviously does not belong to Palinurus nor Pamdirus. 

 There is a general resemblance to a Phyllosoma described by Santucci (1929) from the 

 Red Sea, and regarded by him as probably belonging to Scyllarides latus, but Santucci 

 does not show a palp on the maxillule and does not mention a rostrum. It is fair to 

 assume that the adult must be a genus possessing a rostrum, ^ which excludes Linupanis 

 and, perhaps, Paliniistiis. There remain only Polinurellus and Puerulus. There is no 

 means whatever for deciding between these two genera, but Palimirellus, with its rela- 

 tively large rostrum and pleopod on somite i , seems to be a primitive genus, and the 

 species P. gmidlachi is recorded from Mauritius and may well occur farther west. I 

 regard it, therefore, as a justifiable speculation to attach this generic name to this 



Phyllosoma. 



Genus Scyllarus, Fabricius (Figs. 32-34) 



For the genus Scyllarus the general characters of the Phyllosoma were established by 

 Dohrn, who described in 1870 the first stage of S. arctus hatched from the egg, and by 

 Hornell (1894), while the complete series of nine stages has been worked out by 

 Stephensen (1923). Stephensen's account is very much more precise and convincing 

 than that of Bouvier or Santucci for Palinurus. The general characters of the genus, as 

 founded on the description of Scyllarus arctus, are as follows : 



1 Gilchrist (1916, p. 112) describes a rostrum in the Phyllosoma of Jasus, but it is very doubtful if the 

 structure described can be so interpreted (see above, p. 422). 



