282 REPORT — 1867. 



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

 a young animal may be known is the immature condition of the antennaj, 

 more especially the iiageUa ; now, whilst in the larva of the FaJinunis they 

 are very rudimentary, in Phylhsoma they assume an adult character, and, in 

 the second pair, one that is of a peculiar feature, at least in the species to 

 ^^■hich we refer. (3) The oral appendages appear to be present, though 

 only as the germs of the future parts, whilst in PhijUosoma they appear to 

 exist in a rudimentary condition that assimilates little to a progressive stage. 

 (4) Double branchial vesicles are attached to the coxae of each pair of 

 pereiopoda, whUst none exist in the larva of PaVinurus. "VVe must admit, 

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

 Palinurus branchial 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 perhaps we should not have thought 

 it sufhciently important to have remarked upon, had not M. Gerbe stated 

 that PhyUosoma, like the larva of Palinurus, was Avithout branchial appen- 

 dages ; and M. M.-Edwards remarked that these vesicular aj)pendages are 

 vestiges of the external branch of the limbs. (5) Phi/Uosoma is a tropical 

 genus, and with such we can only compare the larva of Pal'umnis ; two 

 specimens only of the former have been obtained in the British seas, whereas 

 Pcdinurus is very common on our coasts — an argument that might be very 

 forcible 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 Pritz MiiUer, that the larva 

 of Peneus, and probably that of some other prawns, very closely resembles 

 that of the cirripedes and other entomostracous larvaj, 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 indicate that carcfid study 

 of these animals will probably assist in thi'owing considerable light on some 

 of the more profound problems of biological knowledge. 



Several specimens of ScijUams arctus have been taken recently on our 

 coasts. It is some years since Mr. Couch announced the fii'st appearance of 

 this as a British species ; and none has since been recorded until these last 

 two years, when several have been taken near Penzance by Mr. Cornish, and 

 one off the Mewstonc, near the eastern entrance of Plymouth Sound ; two 

 of these were furnished with spawn, and two were found in the stomach of 

 a cod-fish. That which we obtained off the Mewstonc was four inches and 

 a half long, and one of the most interesting additions to our local fauna. 

 This length is half as long again as that recorded by M. Milne-Edwards 

 of the Mediterranean specimens. 



In the dredging list published by this Association, the common lobster of 

 Europe is called Astacus gammarus (L.), rnarinus (Pabr.), and Homarus vul- 

 garis (M.-Edwards). But since the desciiptions of Linnajiis of Crustacea are so 

 very general, and the specific name used by him has been long closely associ- 

 ated with that of a very distinct genus, we think that of Pabiicius (the 

 next in succession) should be adopted. Again, the generic name given by 

 Pabricius, Astacus, although prior to all others, yet included the freshwater 

 genus, with which it is so -closely associated that it would be inconvenient 

 to make an exchange. We therefore propose, in accordance with the rules 

 laid down by this Association, to retain the generic name of M. M.-Edwards 

 and the specific name of Pabricius, and call it Homarus marlnus (Pabr.), 



