LARVAE OF DECAPOD CRUSTACEA 401 



A further difficulty in the study of these forms is the defective condition of the 

 material. In the Discovery specimens the legs are lost from almost every specimen, and 

 this, to judge from published figures, is the general rule. These legs do, in some cases, 

 present striking features which would be useful systematically if available generally for 

 comparison. 



It is difficult to see how further progress can be made in systematic knowledge of 

 Phyllosoma, since conclusive specific determination can only be got by capture of the 

 last stage and observation of the moult to the natant stage. As the late Phyllosomas are 

 high-sea forms, apparently confined to the deeper layers, and only accessible to well- 

 equipped oceanographical expeditions, such observations cannot be expected. Such 

 problems as this could be dealt with at the Bermuda Biological Station, where the deeps 

 of the Atlantic are within so short a distance of an excellent laboratory, but the station 

 at present has neither boat nor gear designed for oceanographical work. 



Genus Palinurus, Fabricius 



The development oi Palinurus vulgaris has been described by Bouvier (19 13) and by 

 Santucci (i925fl), both of whom found nine stages ; but the accounts given of these stages 

 are so incomplete and there are so many contradictions in the two accounts that a 

 thorough re-examination is desirable. It is certain that P. vulgaris is much larger when 

 hatched than Jasus, for example, and the last Phyllosoma, which Bouvier observed to 

 moult to the Puerulus, does not much exceed 20 mm., or only about half the size of some 

 of the Pamdirus larvae. It might be expected, therefore, that there would be fewer 

 stages in its development. I have myself seen very few of the older stages of P. vulgaris, 

 and have not found it possible to fit them into the definitions given by Bouvier and 

 Santucci. There is some reason to suppose that there may be less than nine stages, marked 

 by considerable changes at each moult. 



Characters of the Phyllosoma of Palinurus. 



Fore-body about as wide as long at all stages, and wider than hind-body. Hind- 

 body not concave behind. Abdomen parallel-sided. 



Peduncle of antennule with segment 2 about half length of segment 3. Antenna 

 with spinous process on segment i of peduncle. 



Maxillule with palp. Maxilla with exopod greatly expanded in later stages and 

 fringed with setae. Maxillipede 2 at first without exopod, but with setose exopod 

 in late stages. Maxillipede 3 with setose exopod from stage I. Legs i and 2 with 

 dactylus prolonged into a very long spine. Leg 4 retarded in development, and 

 never so large as leg 3. Leg 5 closely apposed to abdomen, without exopod. 



Maxillipede 3 and legs with coxal spines. 



Palinurus gilchristi, Stebbing (Fig. 14) 

 Three specimens scarcely distinguishable from corresponding stages of P. vulgaris, 

 were taken at the following stations in the neighbourhood of the Cape : 



