5772 Radiata. 



Mr. Gregson exhibited a box of Coleoptera, amongst which were Dyschirius ira- 

 punctipennis and D. politus, and a species of the same genus taken below high-water 

 mark on the Lancashire coast, Hesperophilus arenarius and H. fracticornis, Gripidius 

 Equaseti, Adrostis marginatus (with eggs), Bembidium laterale, &c, which were 

 brought for distribution amongst the members. 



Mr. N. Cooke read a paper ' On the Species of Lepidoptera observed or captured 

 in Ireland during five days' collecting there,' after which he distributed his duplicate 

 captures amongst the members present. — C. S. G. 



Notes on Ascidiae as a source for Diatomacece. — Being engaged, some time ago, in 

 examining some dredged oysler-shells for Diatomacea?, I discovered, on the surface of 

 one of the shells, a cluster of semi-transparent gelatinous bodies, of a yellowish green 

 colour, the shape being, however, not uniform, owing perhaps to their being dead and 

 flaccid. In shape they approached small hazel-nuts. These I took to be Ascidiae of 

 some species, as they were apparently enveloped in an outer mantle or skin of some- 

 what tough consistency. In cutting through this mantle, and towards the centre of 

 the body, a large stomach was exposed, quite distended with what appeared to 

 be brown mud. On examining this under the microscope I was delighted to find it 

 almost entirely composed of Diatomaceae, still quite fresh and full of endochrome. 

 The Diatoms were mostly uncommon forms ; the most conspicuous of these, which 

 occurred in the first specimen I opened, were Coscinodiscus concinnus (in great num- 

 ber and of unusual size), Pleurosigma lanceolatum, nov. sp., Eupodiscus crassus, E. 

 Ralfsii, Eucampia zodiacus, and a curious tubular Rhizosolenia which Mr. Bright- 

 well has named Rhizosolenia styliformis. I have since then examined many 

 Ascidiae from the same source, and have never failed in any instance in obtaining 

 Diatomacea? in abundance ; and these have been mostly species occurring in deep 

 water, and consequently somewhat uncommon and difficult to obtain, unless the col- 

 lector is furnished with an expensive dredging apparatus. Some of the forms are of 

 great rarity, and some are even quite new. I would therefore call the attention of all 

 Diatoraists to this source as an easy and inexpensive method of obtaining good and 

 rare forms, in a comparatively clean state, without much trouble, as the trawling boats 

 are constantly bringing to market the large dredged oysters, which are frequently 

 covered with Ascidiae. The locality where my oysters were obtained is some twenty 

 or thirty miles from the Yorkshire coast, a little to the North of the river H umber, 

 and is known as the " Silver Pits." I give annexed a list of the species detected in 

 merely four gatherings, which will serve to show what may be expected when Ascidiaj 

 are examined from other and possibly more favourable localities. The letter A pre- 

 ceding the name denotes that the species occurs abundantly ; F, that it occurs occa- 

 sionally, though less frequently than the first; R, that it only occurs rarely,— perhaps, 

 for instance, one or two specimens in a slide. 



F Eucampia zodiacus much coarser striae. The valve nearly 



F Pinnularia distans straight, the central line much 



A Pleurosigma lanceolatum, nov. sp., in curved, and with a faint depression 



the way of P. angulatum, but with running across the centre of the 



