Mr. C. Spence Bate on Crustacea. 117 



the birth of the larva. (2) The most certain mark by which a 

 young animal may be known is the immature condition of the 

 antennas, more especially the flagella ; now, whilst in the larva 

 of the Palinurus they are very rudimentary, in Phyllosoma they 

 assume an adult character, and in the second pair one that is 

 of a peculiar feature, at least in the species to which we refer. 

 (3) The oral appendages appear to be present, though only 

 as the germs of the future parts ; whilst in Phyllosoma they 

 appear to exist in a rudimentary condition that assimilates 

 little to a progressive stage. (4) Double branchial vesicles are 

 attached to the coxse of each pair of pereiopoda, whilst none 

 exist in the larva oi Palinurus. We must admit, however, 

 that this argument is not very strong, seeing that in the adult 

 Palinurus such organs are present, and that there must be a 

 period when they first appear ; and it is most probable that 

 their earliest stage is of the most simple character. And per- 

 liaps we should not have thought it sufficiently important to 

 have remarked upon, had not M.Gerbe stated that Phyllosoma^ 

 like the larva of Palinurus ^ was without branchial appendages, 

 and M.M. -Edwards remarked that these vesicular appendages 

 are vestiges of the external branch of the limbs. (5) Phyllo- 

 soma is a tropical genus, and with such we can only compare 

 the larva of Palinurus ; two specimens only of the former have 

 been obtained in the British seas, whereas Palinurus is very 

 common on our coasts — an argument that might be very forci- 

 ble were we not cognizant of the fact that we are quite as much, 

 if not more, in the dark in relation to the development of the 

 common lobster. 



Our ignorance upon these interesting and important points 

 in the history of the Crustacea, together with the discovery of 

 Fritz Miiller that the larva of Peneus^ and probably that of 

 some other prawns, very closely resembles that of the cirripeds 

 and other entomostracous larvse, shows that there is much yet 

 to be done of far more interest to zoological science than the 

 mere discovery of new species to be added to our fauna. The 

 great diversity of structure, and the wonderful variation in the 

 development of animals that possess a great similarity in their 

 adult condition, indicates that careful study of these animals 

 will probably assist in throwing a considerable light on some 

 of the more profound problems of biological knowledge. 



Several specimens oiScyllarus arctus have been taken recently 

 on our coasts. It is some years since Mr. Couch announced 

 the first appearance of this as a British species ; and none has 

 since been recorded until these last two years, when six have 

 been taken near Penzance by Mr. Cornish, and one off the 

 Mewstone, near the eastern entrance of Plymouth Sound ; two 



