44 MEMOIBS OF THE QUEENSLAND MUSEUM. 



THE OCCURRENCE IN BRISBANE RIVER OF 

 THE NEW ZEALAND AMPHIPOD, PARA^ 

 COROPHIUM EXCAVATUM (G. M. THOM- 

 SON). 



By Chas. Chilton, M.A., D.Sc, M.B., CM., LL.D., F.L.S., C.M.Z.S.. Hon. Memblk 

 Roy. Soc. N.S.W., Professor of Biology, Canterbury College, New Zealand. 



(With Text-figures Nos. I to XIX.) 



Towards the end of 1918, I received from Professor T. Harvey Johnston, 

 of the University of Queensland, and honorary Zoologist to the Queensland 

 Museum, a few Crustacea from Brisbane River, sent chiefly because of the 

 boring Isopod, Sphceronia terebrans Bate, which was doing considerable destruc- 

 tion in timber immersed in the water. Among the specimens, however, were 

 numerous examples of a small amphipod evidently belonging to Coropliiura 

 or some allied genus. The male of this species first attracted my attention because 

 of the character of the second gnathopod and the possession of a lobe on the 

 inner side of the end of the penultimate joint of the peduncle of the lower 

 antenna. Later on when I came to examine the females, which differed in the 

 structure of the second gnathopod and in having no lobe on the antenna, I was 

 struck by their resemblance to the descriptions of Paracorophium excavaturn 

 (G. M. Thomson), an amphipod found in brackish waters of New Zealand. In 

 that species no sexual differences had hitherto been described. However, I found 

 on closely examining specimens in my collection that there were some males 

 among them having the characters of the second gnathopod and the lobe on the 

 lower antenna quite similar to those of the Brisbane specimens, and careful 

 comparison shows conclusively that the Brisbane specimens belong to the same 

 species as the New Zealand. I take this opportunity of giving a fuller account 

 of the species than has hitherto been published and of describing the differences 

 between the male and the female. 



Paracorophium excavaturn was described by Mr. Gt. M. Thomson in 1884, 

 under the name Corophium excavaturn, from specimens obtained in Brighton 

 Creek, near Dunedin, the water of which he described as being salt. A little later 

 I received some specimens from Napier, and in January, 1890, I collected a 

 number at Brighton itself at a time when the water in the estuary was nearly 

 fresh or only slightly brackish ; in 1894 I obtained a few specimens from Nelson, 

 also in brackish water. In 1902 Messrs. Lucas^ and Hodgkin obtained specimens 



' Keith Liieas, A Bathymetrieal Survey of the Lakes of New Zealand, Geographical 

 Journal for May. and June, 1904. 



