Miscellaneous. 345 



here so reduced in size as to be quite invisible from above, and only 

 demonstrable with difficulty from below, whence it appears in ordi- 

 nary positions under the microscope as a convex ovuidal or heart- 

 shaped plate ; it, moreover, looks downwards and slightly backwards, 

 instead of upwards and backwards or directly backwards, as it usually 

 does. 



The legs are long, slender, simple, equal in length, rather more 

 than twice as long as the body (including the rostrum), and are com- 

 posed of eight joints, terminated by a weak slightly curved claw. 

 Their three basal joints are as broad as long, equal, and almost glo- 

 bular ; the fourth is club-shaped at the distal end ; the fifth is all 

 but as long as the fourth, and, with the remaining joints, perfectly 

 filiform ; the sixth is shorter and about twice the length of the two 

 last together ; these are subequal. 



millims. 



Length of the body (including the rostrum) 13 



,, „ legs 26 



„ „ second pair of cephalic appendages 10 



„ third „ „ „ ^ 12 



From the linear form of the body and the slenderness of the legs 

 I conclude that rhy specimen is a male — a conclusion by no means 

 invalidated by the presence of the third pair of cephalic aj)pendages, 

 which, being a,pparently invariably developed in both sexes through- 

 out several genera {Nymplion, &c.), consequently possesses no value 

 in the determination of questions of sex. 



Hah. Dredged by the writer at Port Blair, Andaman Islands, in 

 25 fathoms of water, at which depth the bottom was clothed with a 

 dense tangle of delicate filamentous algae so closely resembling the 

 animal in point of colour and form that the latter was with difficulty 

 distinguishable. 



In conclusion, I dedicate the first species of Pycnogonida hitherto 

 discovered in these seas to the memory of the illustrious Danish 

 naturalist whose name is so indissolubly connected with the history 

 both of the Pycnogonida and of the lower Crustacea. — Jo^irnal of 

 the Asiatic Society of Bengal, vol. xlii. part 2 (1873). 



On the Development of Distomum nodulosum. By 0. von Linstow. 



The author has ascertained that Distomum nodulosum is not pro- 

 duced from the Cercaria Planorbis carinati as supposed by De Filippi, 

 but from another form which was not previously known. 



To follow the migrations of this Avorm the author put individuals 

 full of ova into a vase containing freshwater mollusca (Lymneus, 

 Pahulina, Planorbis, Valvata, etc.). The Distoma were soon de- 

 composed and their ova were set free. The first embryos were 

 hatched in two or three days ; they swam about rapidly by 

 means of their vibratile covering. It was in the alimentary canal 

 of certain ChDetopod Annelids by which they had been swallowed 

 that M. von Linstow was best able to follow the first transformations 

 of these larva? ; they had lost their cilia, and there was clearly to be 



