138 



notes on some species of the isopod family 

 Sph>eromid>e, from the South Australian Coast. 



By W. H. Baker, F.L.S. 



[Read June 7, 1908.] 



Plates III. to X. 



In presenting these notes I must acknowledge the great 

 assistance I have had from Dr. Hansen's paper entitled 

 "The Propagation, Structure, and Classification of thei Family 

 Sphaeromidae," in the "Quarterly Journal of Microscopic 

 Science,'' n. series, vol. 49, pt. 1, 1905. Without it it would 

 have been quite impossible for me to treat with any degree 

 of success species of this acknowledged difficult family which 

 have come under my notice from our coast. At the same 

 time it will be seen that my observations do not quite agree 

 with statements in Dr. Hansen's paper regarding the parts 

 occupied by the developing young in some genera. 



In studying the species of this family, the thing that 

 strikes one most is their great variability — this, indeed, is 

 the main cause of the confusion which has held sway in their 

 classification so long ; but a general statement may be made, 

 namely, that the young of both sexes resemble each other, 

 the deviation occurring in adult males and females; that 

 of the young-bearing females of many genera has been shown 

 by Dr. Hansen in the above-mentioned paper. As an in- 

 stance with the males, to take the case of Cymodoce tuber- 

 culosa, Stebbing. In this species there are two. conspicuous 

 processes on the anterior division of the pleon which are not 

 figured or mentioned by the author or by Mr. Whitelegge, 

 who refers at length to the same species from New South 

 Wales; the inference, of course, is that they were not pre- 

 sent in the specimens examined by them, athough Mr. Whit-e- 

 legge speaks of his as being adult males. Another instance 

 will be seen in the case of Ciliccea curtisjnna, Haswell, later on. 



With regard to the young-bearing females, whose mouth 

 parts and viscera have been so much altered, one fails to 

 see how the animal recovers itself after rearing a brood, and 

 is driven to the conclusion that the individual perishes in 

 the effort, and is probably, in some cases at least, perhaps 

 eaten by the brood. In the female of a specie's of Cymodoce 

 which, as yet, I have not been able to identify, I have ob- 

 served the transverse slits in the sternal plates referred to 

 by Dr. Hansen, and have seen well-formed young emerge 

 from under the marsupial plates ; these were somewhat har- 



