PROCEEDINGS OF SCIENTIFIC SOCIETIES. 137 
reception of all those species the males of which have two brands upon the 
interno-median are2 of primaries. or this latter group he coins the name 
Stictoplea. These brands in the Stictoplea he conceives are for purposes 
of strigillation. Then follows a list containing the species under each 
genus of the series contained in the British Museum Cabinets, with notes 
of elucidation. 
March 7, 1878.—Dr. Gwyn JEeFrrreys, Vice-President, in the chair. 
Mr. Charles C. P. Hobkirk, of Huddersfield, was ballotted for, and 
elected a Fellow of the Society. 
Prof. Ray Lankester exhibited and made remarks on a valuable series of 
fossil Walrus tusks (Trichecodon Huzleyi) from the Suffolk Crag, sent to 
him for examination by Mr. J. E. Taylor, of the Ipswich Museum. 
Mr. Rich exhibited some examples of a new variety of Helix virgata. 
forwarded to him from Ireland. 
The first zoological paper read was “On some New Species of 
Nudibranchiate Mollusca from the Eastern Seas,” by Dr. Cuthbert Colling- 
wood. The author remarked that zoologists and voyagers who pay but 
brief visits to the tropical coasts are less likely to obtain new or interesting 
forms of the Nudibranchiates than are residents searching carefully within 
limited areas. Thus he accounts for Sir W. Eljiot’s Madras, and Kelaart’s 
Ceylon, gatherings surpassing expeditions fully equipped for collection. 
The, gay colouring of the group is equally found on our own shores, less 
-climatically favoured, as on those of the tropics. Seasonal and other 
influences probably have much to do with abundance or scarcity of species, 
even in a given locality, where previously known to exist. Dr. Collingwood 
noticed some curious instances in which specimens isolated in a dish of 
sea-water spontaneously, and very neatly, amputate the region of their own 
mouths. He then described the following sixteen new species, and 
exhibited coloured drawings from Nature, showing the animals in the 
expanded and contracted conditions :—{1) Doris pecten, (2) D. crescentica, 
(8) Chromodoris iris, (4) C. Bullockii, (5) C. aureo-purpurea, (6) C. tumuli- 
jera, (i) C. tenuis, (8) C. funerea, (9) C. Alderi, (10) Albania formosa, 
(11) Triopa principis-Wallia, (12) Trevelyana felis, (18) Doridopsis arbo- 
rescens, (14) Phyllidis spectabilis, (15) Freyeria variabilis, (16) Bornella 
marmorata. 
In the absence of the author, Dr. Patrick Manson, Dr. Cobbold commu- 
nicated a paper “On the development of Filaria sanguis-hominis, and on 
_the Mosquito considered as a Nurse.” He pointed out that development 
cannot progress far in the host containing the parent worm ; that the embryo 
must escape from the original host; and that in the case in question the 
mosquito is found to be the nurse. The latter term, “nurse,” he employed 
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