JOTTINGS FROM THE BIOLOGICAL LABORATORY 
OF SYDNEY UNIVERSITY. 
By William A. Haswell, M.A., D.Sc., Lecturer on Biology. 
11. On Sacculina infesting Australian Crabs. 
In specimens of Nectocarcinus integrifrons, a Brachyuran fre- 
quently brought up in considerable numbers in the trawl in Port 
Jackson, and of Thalamita sima, which is not quite so common, there 
is often to be observed below the abdomen a large, firm but soft, 
brown body, which on examination proves to be a Rhizocephalan of 
genus Sacculina. The infested crabs have all hitherto, with a 
single exception, proved to be males ; these had all undergone a 
singular malformation, and I found that I was enabled to extend 
to these Australian species the very remarkable observations made 
in the last two years by Giard on the European crabs — Stenor- 
hynchus phalangium, Carcinus mcRnas, and Portunus holsatus* At 
first sight on examining one of these specimens of Nectocarcinus ov 
Thalamita harbouring the Sacculina^ one might be disposed unhesi- 
tatingly to put it down as a female, the broad bulging abdomen 
concealing a mass of eggs ; but on turning the abdomen back one 
found, not the expected eggs attached to the abdominal appendages, 
but the parasite above-mentioned fitting in with perfect accuracy 
so as to be completely covered and protected by the abdomen when 
the parts were in place, and firmly fixed to the crab by a short 
stalk perforating the sternal membrane of the third segment. 
Not only, however, were the eggsj found to be replaced by this 
parasitic crustacean, but the sexual apertures were found to be 
situated on the last .segment of the cephalothorax ; and the pos- 
* “ Parasitic castration and its influence upon the external characters of 
male sex in the Decapod Crustacea,” (translated from tlie “ llulletin scien- 
tifique du Nord Ann. Mag. N. Hist. (.5), Vol. XIX. pp. .325-.S45 (1887)* 
For the life-history of the parasite, see Yves Delage, “ Evolution de la 
Sacculine,” Arch, de Zool. exp. et g6n. (2), Tome II. (1884). 
