Mr. E. Lovett. 125 



■30.— Some Observations on the Embryology of the 



PODOPHTHALMA, OR StALK-EYED CRUSTACEA. 



By Mr. Edward Lovett. 

 [Read i$th March, 1882.] 

 Having recently had the opportunity of examining a large 

 number of the stalk-eyed forms of Crustacea, collected from a 

 variety of localities and depths, and extending over a period 

 of about eighteen months, I noticed some mterestmg features 

 with regard to the ova of these animals that seemed worthy of 

 .attention. ... 



In the first place, several species were with ova, whilst 

 ■others from the same locality were not ; secondly, some species 

 •were with ova at periods totally different from the time recorded 

 by authors on this subject ; thirdly, the ova of various species 

 were, as regards their size, out of all proportion with the ova 

 of other species ; fourthly, the protective power of the parent 

 differed widely in species living under various conditions ; and 

 fifthly, the ova themselves underwent great changes in appear- 

 ance as they approached maturity. 



As regards the first of these facts, it would appear that 

 many species may be double-brooded, and although I have 

 noticed that it is during the early summer months that ova is 

 generally carried in the immature state, yet there are many 

 species that are later and others that are earlier than this. 

 In May I obtained the ova, in an immature state, of Portiinus 

 marmoreiis, Palcemon serratus, P. squilla, Porhimnus latipes, 

 Gebia delttira, Scyllarus arctus, S-c. I had, however, obtained 

 the ova of several species in January, February, and March. 

 In September I obtained the mature ova of Xantho Jlorida, 

 X. rivulosa, and Achcsns Cranchii, and in December the semi- 

 mature ova of Hyas coarctatus. It thus appears that the 

 spawning season extends, in different species, over the whole 

 year, and that more or less favoured localities causing a 

 variation in the spawning season of particular species may 

 account for the discrepancy to which I have referred in the 

 second place. •, ,• 



Taking as an example a species of somewhat wide distribu- 

 tion, I have found that specimens from the South-west parts of 

 the English coast, and from the Channel Islands in particular, 

 attain to a more developed condition in many ways; and it is 

 thus that we find species with ova in such favourable localities 

 at a time when the same species from the Thames estuary or 

 the North-east coast would be without ; hence possibly arises 

 the difference in time recorded by different authors as to the 

 spawning season of one and the same species. 



Not only does this variation obtain under these conditions, 



B q 



