DEVELOPMENT OF PALINURUS VULGARIS. 149 



in lengtli, since his figure of the appendages in this form is not 

 conclusive^ but suggests the idea that he has figured the rudimentary 

 first maxilliped and mistaken it for the second maxilla. 



It is more interesting to note that of the stages obtained and 

 figured by Claus at Messina^ while the oldest and youngest belong 

 to Scyllarus, all the others, that is all those figured on Z. f. w. Z., 

 Bd. xiii, pi. xxvi, are stages in the development of Palinurus vul- 

 garis. The youngest of these stages is described as 4 mm. long, 

 and therefore has not long been hatched. It agrees, except in one 

 or two very minute details, due, I think, to slight mistakes in draw- 

 ing, with the newly hatched larva I have described, and, above all, 

 both in the description and figure of Claus, the first maxilliped is 

 represented as a short papilla-like process, exactly similar to that 

 in my specimens. Claus figures and describes two other stages, 

 which also I identify as belonging to Falinurus vulgaris ; one of 

 these is 14 mm. long, tlie other 21 mm. ; both, therefore, older 

 than the oldest of my specimens. In the former, the thorax extends 

 back over the third maxilliped in the older stage (21 mm.), still 

 further, covering the base of the first pereiopod. In this oldest 

 stage of Claus the antennae have almost acquired the adult form, 

 and the fourth and fifth pereiopoda are longer than the abdomen, 

 although the fifth is still destitute of exopodite. In both these 

 older stages the first maxilliped has considerably developed, consist- 

 ing of a long cylindrical appendage borne on a short stump. 



Thus it is evident that the Phyllosoma of Palinurus vulgaris 

 reaches a length of more than 21 mm. before it begins to lose the 

 characteristic flattened form of the larva. The smallest Palinurus 

 observed by Richters was 25 mm., or 1 inch in length, and had all 

 the characters of the adult. The later stages of transition between 

 the Phyllosoma and the youug Palinurus have still to be discovered. 



I hoped to obtain stages later than those I have here described, 

 but unfortunately the weather during the latter half of July and the 

 whole of August was persistently stormy, and it was impossible to 

 collect in the open sea. In September I resumed my expeditions, 

 but obtained no more Phyllosomes. 



