LARVAL AND POST-LARVAL STAGES OF JASUS LALANDII. 101 



Larval and Post-Larval Stages of Jasus lalandii (Milne Edw.), Ortmann. 

 By J. D. F. Gilchrist, M.A., D.Sc, Ph.D., F.L.S. 



■■■a 



[Plates 12-17, and 12 Text-iigures.] 

 [Read 2nd March, 1916.] 



In the Journal of the Linnean Society, Zoology, vol. xxxii. October (191.3)^ 

 p. 225, I described the newly-hatched larva o£ Jasus lalandii. Since then 

 sufficient material has been procured to give a fairly complete account of 

 later stages. This includes the immediately succeeding stage (1'7 mm. m 

 length), numerous specimens of which were got by rearing from the egg and 

 by tow-netting in Table Bay^ a much less numerous series procured further 

 from the shore (from 3'8 to 37 mm. in length), and, finally, a number of 

 specimens of the "puerulus'^ stage (from 22 to 26 mm.), and of succeeding 

 stages in which the cuticle becomes calcified. 



That all these are stages of Jasus lalandii seems probable from their 

 general resemblance, and from a comparison with phyllosomas found at 

 other places on the South African coast. The evidence from locality is also 

 particularly trustworthy, owing to the distribution of the Cape crawfish and 

 other South African Loricata. Jasus lalandii is abundant on the west coast 

 from Cape Point northwards, but to the east of this it is very scarce, and 

 has not been found on the east coast north of Port Elizabeth. On the 

 south coast a Palinurus has been found, but it is not abundant. On the east 

 coast a Panidirus is fairly abundant, and Scyllarides is common in Natal 

 waters. The phyllosomas referred to Jasus have all been found on the west 

 coast. Three other kinds have been procured from the south and east coasts : 

 one, which grows to a very large size, is, on the evidence of its flat tentacles, 

 referable to Scyllarides, the other two probably to Palinurus and Panidirus. 

 The puerulus stages referred to Jasus have all been found in Table Bay ; 

 two other kinds, obviously different, have been found on the east and south 

 coasts and are probably referable to the other South African Loricata 

 mentioned — one with a pair of ventral spines to Palinurus, and the other 

 with lono- antennular flao;ella to Panidirus. 



In the following account a more detailed description of the first or 

 " naupliosoma " stage, for purposes of comparison, is given ; a typical 

 phyllosoma stage of 1*7 mm. is described ; succeeding stages of 3'8, 24, 26, 

 33, 35, and 37 mm. are then described in such detail as seems necessary, and, 

 lastly, some points, which seem to be of significance, are noted in the 

 " puerulus '' stage. 



LINN. JOURN. ZOOLOGY, VOL. XXXIII. 8 



