Gatty Marine Laboratory ^ St. Andrews. 299 



process was visible below the terminal hook, though it wis 

 by no means distinct. 



The ventral cirrus is remarkably elongate in proportion to 

 the size of the foot. It extends considerably beyond tlie tip 

 of the latter. In shape it is constricted at the base, slii^htly 

 dilates for some distance, and then diminishes a little toward 

 the tip. 



'i'his form therefcire differs from the variety procured by the 

 * Porcupine' in having more numerous articulations in the dorsal 

 cirri, viz. eighteen to twenty, yet Malrngren gives twenty-two 

 to twenty-seven as the typical number. Tiie great length of 

 the ventral cirrus, which extends considerably beyond the tip 

 of the setigerous region, is also noteworthy. The number of 

 the articulations in the dorsal cirri seems to vary mucli, ior in 

 an example from the deep water off !St. Andrews Bay they are 

 even more numerous than Malmgren observes. Moreover, 

 the shorter and wider ventral cirrus in such forms also leaves 

 the question open as to whether all can be included under the 

 original species. 



5. On the Boring 0/ Polydora in Australian Oysters. 



An interesting Report to the Fisheries Commissioners of 

 New South Wales by Mr. Thomas Whitelegge, Zoologist to 

 the Australian Museum, 'On the Worm Disease affecting the 

 Oysters of New South Wales ' *, affords an opportunity of 

 glancing at the effects of this widely distributed genus in 

 colonial waters, more especially as a considerable collection of 

 Australian oysters exists in the University Museum. 



Mr. Whitelegge appears to have overlooked the earlier 

 paper by Prof. Haswell t» who examined the oysters from the 

 same beds, viz. Newcastle, Hunter River, and described the 

 blisters formed by the thin layers of nacreous substance over 

 the fine black mud in the valves, and suggests that the exten- 

 sive destruction of the oyster-shells in Hunter River may be 

 connected with the muddiness of the water produced by in- 

 creased traffic. Prof. Haswell found two species oi Polydora 

 in the oyster-shells, one of which is new, viz. Polydora poly ^ 

 hranchia, the other being P. ciliata. 



The author (Mr. Whitelegge) carried out his observations 

 at Newcastle (Hunter River), where there are many beds, 



* 1890. Kindly forwarded hj the Hon. J. H. AVant, who has taken 

 great interest in the tishories of N' ew South Wales. 



t • Jottings from the Biol. Laboratory, Sydney University,' p •'>7o 

 (IbSO). ' J tf- - 



