18 
collected by Mr. F. A. Potts in the N.. Pacific in 1911, with a 
Note on Micronereis as a Representative of the Ancestral Type 
of the Nereide ; (2) On the Genera Ceratocephale Malmgren and 
Tylorrhynchus Grube. 
Mr. A. Kyyvert Torron contributed an account of the 
Structure and Development of the Caudal Skeleton of the 
Teleostean Fish Pleuragramma antarcticum. 
Mr. G. C. Rosgox,.B.A., read a report on Mollusca from 
Dutch New Guinea collected by the British Ornithologists’ 
Union and Wollaston Expeditions. In general, the collection 
appears to endorse Hedley’s views as to the Oriental affinities of 
the Papuan molluscan fauna. Though numerically small in 
species and individuals, the collection has yielded two genera 
and three new species, the anatomy of all of which is described. 
The two new genera, which were obtained from considerable 
altitudes, viz. 10,500 ft. and 14,200 ft. respectively, are of 
considerable interest, though their precise affinities are as yet 
uncertain. In any case they cannot be regarded as typical 
members of the Xonitide, though an aggregate of anatomical 
characters exhibits the characters of that family. An account of 
the anatomy of Papwina litwus (Lesson) is given, and dis- 
crepancy between the anatomical and conchological relationships 
of a new species of Papuina is discussed. 
This paper will be published in the TRANsacrions in due 
course. 
Prof, H. Maxwett Lerroy, M.A., F.Z.S., Curator of Insects, 
communicated Mr. P. R. Awati’s paper on “The Mechanism of 
Suction in Lygus pabulinus Linn.,” a Capsid bug injurious to 
the foliage of the potato, on which it feeds. A detailed de- 
scription of the morphology and anatomy of those organs of the 
head concerned in sucking the plant-juices is followed by an 
account of their mode of action, in part deduced from their 
structure and arrangement, in part derived from observation 
of the living insect. The potato-leaf is pierced by the conjoined 
maxillary and mandibular stylets, the labrum and labium serving 
to direct and steady them at the point of puncture. The inner 
(maxillary) stylets are grooved along their apposed surfaces in 
such a way as to form two canals, one conducting to the cavity of 
the pharynx, the other to a salivary pump in connection with the 
salivary glands. Suction is effected by muscles which raise the 
flexible dorsal wall of the pharynx. 
The investigation was conducted by means of serial sections, in 
the making of which attention to certain details of technique was 
found to be essential. An historical summary is given of work 
on the homologies of the mouth-parts of the Rhynchota. 
